[Icons NTP] Using flag to enable large icons on the NTP.

A follow-up to crrev.com/1026053003: We need to pass the flag for
enabling icon NTP to the 3 end points that use them. One endpoint
(searchbox_extetnsion.cc) is in the Renderer process, and the flag (as
command line) needs to be propagated. To obey existing dependencies,
the flags kDisableIconNtp and kEnableIconNtp need to be moved to
ui_base_witches.*. As for enabling using variation, the code is kept
near the end points to avoid adding dependency to ui_base.

BUG=467712

Review URL: https://codereview.chromium.org/1043753002

Cr-Commit-Position: refs/heads/master@{#323570}

chrome/browser/favicon/favicon_tab_helper.cc

@@ -4,6 +4,8 @@
 
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 
+#include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ -20,7 +22,6 @@
 #include "components/favicon/core/favicon_service.h"
 #include "components/favicon_base/favicon_types.h"
 #include "components/history/core/browser/history_service.h"
-#include "components/variations/variations_associated_data.h"
 #include "content/public/browser/favicon_status.h"
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/navigation_controller.h"
@@ -31,6 +32,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/favicon_url.h"
+#include "ui/base/ui_base_switches.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
@@ -45,9 +47,19 @@ DEFINE_WEB_CONTENTS_USER_DATA_KEY(FaviconTabHelper);
 
 namespace {
 
-// Returns whether icon NTP is enabled.
+// Returns whether icon NTP is enabled by experiment.
+// TODO(huangs): Remove all 3 copies of this routine once Icon NTP launches.
 bool IsIconNTPEnabled() {
-  return variations::GetVariationParamValue("IconNTP", "state") == "enabled";
+  // Note: It's important to query the field trial state first, to ensure that
+  // UMA reports the correct group.
+  const std::string group_name = base::FieldTrialList::FindFullName("IconNTP");
+  using base::CommandLine;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableIconNtp))
+    return false;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableIconNtp))
+    return true;
+
+  return StartsWithASCII(group_name, "Enabled", true);
 }
 
 #if defined(OS_ANDROID) || defined(OS_IOS)

chrome/browser/search/local_ntp_source.cc

@@ -4,6 +4,7 @@
 
 #include "chrome/browser/search/local_ntp_source.h"
 
+#include "base/command_line.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
@@ -20,12 +21,12 @@
 #include "chrome/grit/generated_resources.h"
 #include "components/search_engines/template_url_prepopulate_data.h"
 #include "components/search_engines/template_url_service.h"
-#include "components/variations/variations_associated_data.h"
 #include "grit/browser_resources.h"
 #include "grit/theme_resources.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/base/ui_base_switches.h"
 #include "ui/base/webui/jstemplate_builder.h"
 #include "ui/base/webui/web_ui_util.h"
 #include "ui/resources/grit/ui_resources.h"
@@ -81,9 +82,19 @@ bool DefaultSearchProviderIsGoogle(Profile* profile) {
        SEARCH_ENGINE_GOOGLE);
 }
 
-// Returns whether icon NTP is enabled.
+// Returns whether icon NTP is enabled by experiment.
+// TODO(huangs): Remove all 3 copies of this routine once Icon NTP launches.
 bool IsIconNTPEnabled() {
-  return variations::GetVariationParamValue("IconNTP", "state") == "enabled";
+  // Note: It's important to query the field trial state first, to ensure that
+  // UMA reports the correct group.
+  const std::string group_name = base::FieldTrialList::FindFullName("IconNTP");
+  using base::CommandLine;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableIconNtp))
+    return false;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableIconNtp))
+    return true;
+
+  return StartsWithASCII(group_name, "Enabled", true);
 }
 
 // Returns whether we are in the Fast NTP experiment or not.

chrome/common/chrome_switches.cc

@@ -271,9 +271,6 @@ const char kDisableExtensionsFileAccessCheck[] =
 const char kDisableExtensionsHttpThrottling[] =
     "disable-extensions-http-throttling";
 
-// Disables large icons on the New Tab page.
-const char kDisableIconNtp[]                = "disable-icon-ntp";
-
 // Don't resolve hostnames to IPv6 addresses. This can be used when debugging
 // issues relating to IPv6, but shouldn't otherwise be needed. Be sure to file
 // bugs if something isn't working properly in the presence of IPv6. This flag
@@ -466,9 +463,6 @@ const char kEnableExtensionActivityLogTesting[] =
 // crbug.com/142458 .
 const char kEnableFastUnload[]         = "enable-fast-unload";
 
-// Enables large icons on the New Tab page.
-const char kEnableIconNtp[]                 = "enable-icon-ntp";
-
 // Enable opt-in for the collection of invalid TLS/SSL certificate chains.
 const char kEnableInvalidCertCollection[] = "enable-invalid-cert-collection";
 

chrome/common/chrome_switches.h

@@ -80,7 +80,6 @@ extern const char kDisableDomainReliability[];
 extern const char kDisableExtensionsFileAccessCheck[];
 extern const char kDisableExtensionsHttpThrottling[];
 extern const char kDisableExtensions[];
-extern const char kDisableIconNtp[];
 extern const char kDisableIPv6[];
 extern const char kDisableJavaScriptHarmonyShipping[];
 extern const char kDisableMinimizeOnSecondLauncherItemClick[];
@@ -135,7 +134,6 @@ extern const char kEnableExperimentalHotwordHardware[];
 extern const char kEnableExtensionActivityLogging[];
 extern const char kEnableExtensionActivityLogTesting[];
 extern const char kEnableFastUnload[];
-extern const char kEnableIconNtp[];
 extern const char kEnableInvalidCertCollection[];
 extern const char kEnableIPv6[];
 extern const char kEnableLinkableEphemeralApps[];

chrome/renderer/searchbox/searchbox_extension.cc

@@ -4,8 +4,10 @@
 
 #include "chrome/renderer/searchbox/searchbox_extension.h"
 
+#include "base/command_line.h"
 #include "base/i18n/rtl.h"
 #include "base/json/string_escape.h"
+#include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ -16,14 +18,14 @@
 #include "chrome/grit/renderer_resources.h"
 #include "chrome/renderer/searchbox/searchbox.h"
 #include "components/crx_file/id_util.h"
-#include "components/variations/variations_associated_data.h"
 #include "content/public/renderer/render_view.h"
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebScriptSource.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/base/ui_base_switches.h"
 #include "ui/base/window_open_disposition.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "url/gurl.h"
@@ -62,9 +64,19 @@ base::string16 V8ValueToUTF16(v8::Handle<v8::Value> v) {
   return base::string16(reinterpret_cast<const base::char16*>(*s), s.length());
 }
 
-// Returns whether we should use large icons on NTP.
+// Returns whether icon NTP is enabled by experiment.
+// TODO(huangs): Remove all 3 copies of this routine once Icon NTP launches.
 bool IsIconNTPEnabled() {
-  return variations::GetVariationParamValue("IconNTP", "state") == "enabled";
+  // Note: It's important to query the field trial state first, to ensure that
+  // UMA reports the correct group.
+  const std::string group_name = base::FieldTrialList::FindFullName("IconNTP");
+  using base::CommandLine;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableIconNtp))
+    return false;
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableIconNtp))
+    return true;
+
+  return StartsWithASCII(group_name, "Enabled", true);
 }
 
 // Converts string16 to V8 String.

content/browser/renderer_host/render_process_host_impl.cc

@@ -1219,6 +1219,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kDisableGpuVsync,
     switches::kDisableLowResTiling,
     switches::kDisableHistogramCustomizer,
+    switches::kDisableIconNtp,
     switches::kDisableLCDText,
     switches::kDisableLocalStorage,
     switches::kDisableLogging,
@@ -1253,6 +1254,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableGPUClientLogging,
     switches::kEnableGpuClientTracing,
     switches::kEnableGPUServiceLogging,
+    switches::kEnableIconNtp,
     switches::kEnableLinkDisambiguationPopup,
     switches::kEnableLowResTiling,
     switches::kEnableInbandTextTracks,

ui/base/ui_base_switches.cc

@@ -15,6 +15,9 @@ const char kDisableRemoteCoreAnimation[] = "disable-remote-core-animation";
 // Disables use of DWM composition for top level windows.
 const char kDisableDwmComposition[] = "disable-dwm-composition";
 
+// Disables large icons on the New Tab page.
+const char kDisableIconNtp[] = "disable-icon-ntp";
+
 // Disables an experimental focus manager to track text input clients.
 const char kDisableTextInputFocusManager[] = "disable-text-input-focus-manager";
 
@@ -30,6 +33,9 @@ const char kDisableTouchEditing[] = "disable-touch-editing";
 // Disables additional visual feedback to touch input.
 const char kDisableTouchFeedback[] = "disable-touch-feedback";
 
+// Enables large icons on the New Tab page.
+const char kEnableIconNtp[] = "enable-icon-ntp";
+
 // Enables a zoomed popup bubble that allows the user to select a link.
 const char kEnableLinkDisambiguationPopup[] =
     "enable-link-disambiguation-popup";

ui/base/ui_base_switches.h

@@ -17,11 +17,13 @@ UI_BASE_EXPORT extern const char kDisableRemoteCoreAnimation[];
 #endif
 
 UI_BASE_EXPORT extern const char kDisableDwmComposition[];
+UI_BASE_EXPORT extern const char kDisableIconNtp[];
 UI_BASE_EXPORT extern const char kDisableTextInputFocusManager[];
 UI_BASE_EXPORT extern const char kDisableTouchAdjustment[];
 UI_BASE_EXPORT extern const char kDisableTouchDragDrop[];
 UI_BASE_EXPORT extern const char kDisableTouchEditing[];
 UI_BASE_EXPORT extern const char kDisableTouchFeedback[];
+UI_BASE_EXPORT extern const char kEnableIconNtp[];
 UI_BASE_EXPORT extern const char kEnableLinkDisambiguationPopup[];
 UI_BASE_EXPORT extern const char kEnableTextInputFocusManager[];
 UI_BASE_EXPORT extern const char kEnableTouchDragDrop[];