Convert ChromeViewMsg_SetFieldTrialGroup to use mojo.

BUG=577685

Review-Url: https://codereview.chromium.org/2642263002
Cr-Commit-Position: refs/heads/master@{#448132}

chrome/browser/metrics/field_trial_synchronizer.cc

@@ -7,7 +7,7 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/threading/thread.h"
-#include "chrome/common/render_messages.h"
+#include "chrome/common/renderer_configuration.mojom.h"
 #include "components/variations/variations_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
@@ -42,8 +42,13 @@ void FieldTrialSynchronizer::NotifyAllRenderers(
   for (content::RenderProcessHost::iterator it(
           content::RenderProcessHost::AllHostsIterator());
        !it.IsAtEnd(); it.Advance()) {
-    it.GetCurrentValue()->Send(new ChromeViewMsg_SetFieldTrialGroup(
-        field_trial_name, group_name));
+    IPC::ChannelProxy* channel = it.GetCurrentValue()->GetChannel();
+    // channel might be null in tests.
+    if (channel) {
+      chrome::mojom::RendererConfigurationAssociatedPtr renderer_configuration;
+      channel->GetRemoteAssociatedInterface(&renderer_configuration);
+      renderer_configuration->SetFieldTrialGroup(field_trial_name, group_name);
+    }
   }
 }
 

chrome/common/render_messages.h

@@ -124,12 +124,6 @@ IPC_MESSAGE_ROUTED1(ChromeViewMsg_WebUIJavaScript,
 IPC_MESSAGE_ROUTED1(ChromeViewMsg_LoadBlockedPlugins,
                     std::string /* identifier */)
 
-// Tells the renderer to create a FieldTrial, and by using a 100% probability
-// for the FieldTrial, forces the FieldTrial to have assigned group name.
-IPC_MESSAGE_CONTROL2(ChromeViewMsg_SetFieldTrialGroup,
-                     std::string /* field trial name */,
-                     std::string /* group name that was assigned. */)
-
 // Sent to allow or forbid the running of insecure mixed-content.
 IPC_MESSAGE_ROUTED1(ChromeViewMsg_SetAllowRunningInsecureContent,
                     bool /* allowed */)

chrome/common/renderer_configuration.mojom

@@ -15,4 +15,10 @@ interface RendererConfiguration {
   // Set the content setting rules stored by the renderer.
   SetContentSettingRules(
       content_settings.mojom.RendererContentSettingRules rules);
+
+  // Tells the renderer to create a FieldTrial, and by using a 100% probability
+  // for the FieldTrial, forces the FieldTrial to have assigned group name.
+  //
+  // See base/metrics/field_trial.h for more information.
+  SetFieldTrialGroup(string trial_name, string group_name);
 };

chrome/renderer/chrome_render_thread_observer.cc

@@ -288,16 +288,6 @@ void ChromeRenderThreadObserver::UnregisterMojoInterfaces(
       chrome::mojom::RendererConfiguration::Name_);
 }
 
-bool ChromeRenderThreadObserver::OnControlMessageReceived(
-    const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(ChromeRenderThreadObserver, message)
-    IPC_MESSAGE_HANDLER(ChromeViewMsg_SetFieldTrialGroup, OnSetFieldTrialGroup)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
 void ChromeRenderThreadObserver::OnRenderProcessShutdown() {
   visited_link_slave_.reset();
 
@@ -324,17 +314,17 @@ void ChromeRenderThreadObserver::SetContentSettingRules(
   content_setting_rules_ = rules;
 }
 
-void ChromeRenderThreadObserver::OnRendererConfigurationAssociatedRequest(
-    chrome::mojom::RendererConfigurationAssociatedRequest request) {
-  renderer_configuration_bindings_.AddBinding(this, std::move(request));
-}
-
-void ChromeRenderThreadObserver::OnSetFieldTrialGroup(
+void ChromeRenderThreadObserver::SetFieldTrialGroup(
     const std::string& trial_name,
     const std::string& group_name) {
   field_trial_syncer_.OnSetFieldTrialGroup(trial_name, group_name);
 }
 
+void ChromeRenderThreadObserver::OnRendererConfigurationAssociatedRequest(
+    chrome::mojom::RendererConfigurationAssociatedRequest request) {
+  renderer_configuration_bindings_.AddBinding(this, std::move(request));
+}
+
 const RendererContentSettingRules*
 ChromeRenderThreadObserver::content_setting_rules() const {
   return &content_setting_rules_;

chrome/renderer/chrome_render_thread_observer.h

@@ -53,7 +53,6 @@ class ChromeRenderThreadObserver : public content::RenderThreadObserver,
       content::AssociatedInterfaceRegistry* associated_interfaces) override;
   void UnregisterMojoInterfaces(
       content::AssociatedInterfaceRegistry* associated_interfaces) override;
-  bool OnControlMessageReceived(const IPC::Message& message) override;
   void OnRenderProcessShutdown() override;
 
   // base::FieldTrialList::Observer:
@@ -64,13 +63,12 @@ class ChromeRenderThreadObserver : public content::RenderThreadObserver,
   void SetInitialConfiguration(bool is_incognito_process) override;
   void SetContentSettingRules(
       const RendererContentSettingRules& rules) override;
+  void SetFieldTrialGroup(const std::string& trial_name,
+                          const std::string& group_name) override;
 
   void OnRendererConfigurationAssociatedRequest(
       chrome::mojom::RendererConfigurationAssociatedRequest request);
 
-  void OnSetFieldTrialGroup(const std::string& trial_name,
-                            const std::string& group_name);
-
   static bool is_incognito_process_;
   std::unique_ptr<content::ResourceDispatcherDelegate> resource_delegate_;
   RendererContentSettingRules content_setting_rules_;