Generate chrome_300_percent.pak

This CL updates chrome/chrome_resources.gyp to generate the
chrome_300_percent.pak file (via the newly-added
chrome/chrome_repack_chrome_300_percent.gypi).

Several .grd files have been updated to generate the
*_300_percent.pak files that are used to create
chrome_300_percent.pak.

This CL doesn't add any assets but grit complains if the
necessary default_300_percent directories are not present
so this CL adds placeholder files in these directories until
real assets are added (which is tracked by crbug.com/423755).

Since there are no assets in the *_300_percent directories,
grit will fallback to using the 1x versions when generating the
*_300_percent.pak files.

Note that 300 percent support will be enabled in
ui/base/resources by a subsequent CL
(https://chromiumcodereview.appspot.com/646773004/).

BUG=423762

Review URL: https://codereview.chromium.org/633373010

Cr-Commit-Position: refs/heads/master@{#300869}

chrome/app/theme/theme_resources.grd

@@ -18,6 +18,7 @@
     <output filename="grit/theme_resources_map.h" type="resource_map_header" context="default_100_percent" />
     <output filename="theme_resources_100_percent.pak" type="data_package" context="default_100_percent" />
     <output filename="theme_resources_200_percent.pak" type="data_package" context="default_200_percent" />
+    <output filename="theme_resources_300_percent.pak" type="data_package" context="default_300_percent" />
   </outputs>
   <release seq="1">
     <structures fallback_to_low_resolution="true">

chrome/chrome_ios_bundle_resources.gypi

@@ -9,6 +9,7 @@
   'mac_bundle_resources': [
     '<(SHARED_INTERMEDIATE_DIR)/repack/chrome_100_percent.pak',
     '<(SHARED_INTERMEDIATE_DIR)/repack/chrome_200_percent.pak',
+    '<(SHARED_INTERMEDIATE_DIR)/repack/chrome_300_percent.pak',
     '<(SHARED_INTERMEDIATE_DIR)/repack/resources.pak',
     '<!@pymod_do_main(repack_locales -o -p <(OS) -g <(grit_out_dir) -s <(SHARED_INTERMEDIATE_DIR) -x <(SHARED_INTERMEDIATE_DIR) <(locales))',
   ],

chrome/chrome_repack_chrome_300_percent.gypi

@@ -0,0 +1,20 @@
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+{
+  # GN version: //chrome:repack_chrome_300_percent
+  'action_name': 'repack_chrome_resources_300_percent',
+  'variables': {
+    'pak_inputs': [
+      # Only iOS generates 300 percent pak files so the inputs will need to be
+      # updated if other platforms need 300 percent support.
+      '<(SHARED_INTERMEDIATE_DIR)/components/components_resources_300_percent.pak',
+      '<(SHARED_INTERMEDIATE_DIR)/ui/resources/ui_resources_300_percent.pak',
+      # TODO(ios): Remove the dependency on renderer_resources.
+      '<(grit_out_dir)/renderer_resources_300_percent.pak',
+      '<(grit_out_dir)/theme_resources_300_percent.pak',
+    ],
+    'pak_output': '<(SHARED_INTERMEDIATE_DIR)/repack/chrome_300_percent.pak',
+  },
+  'includes': [ '../build/repack_action.gypi' ],
+}

chrome/chrome_resources.gyp

@@ -443,6 +443,16 @@
             '<(DEPTH)/content/app/strings/content_strings.gyp:content_strings',
             '<(DEPTH)/third_party/WebKit/public/blink_resources.gyp:blink_resources',
           ],
+        }, {  # else
+          'actions': [
+            {
+              'conditions': [
+                ['OS == "ios"', {
+                  'includes': ['chrome_repack_chrome_300_percent.gypi']
+                }],
+              ],
+            },
+          ],
         }],
         ['use_ash==1', {
           'dependencies': [

chrome/renderer/resources/renderer_resources.grd

@@ -6,6 +6,7 @@
     </output>
     <output filename="renderer_resources_100_percent.pak" type="data_package" context="default_100_percent" />
     <output filename="renderer_resources_200_percent.pak" type="data_package" context="default_200_percent" />
+    <output filename="renderer_resources_300_percent.pak" type="data_package" context="default_300_percent" />
   </outputs>
   <release seq="1">
     <structures fallback_to_low_resolution="true">

components/resources/components_scaled_resources.grd

@@ -6,6 +6,7 @@
     </output>
     <output filename="components_resources_100_percent.pak" type="data_package" context="default_100_percent" />
     <output filename="components_resources_200_percent.pak" type="data_package" context="default_200_percent" />
+    <output filename="components_resources_300_percent.pak" type="data_package" context="default_300_percent" />
   </outputs>
   <release seq="1">
     <structures fallback_to_low_resolution="true">

ui/resources/ui_resources.grd

@@ -8,6 +8,7 @@
     <output filename="grit/ui_resources_map.h" type="resource_map_header" context="default_100_percent" />
     <output filename="ui_resources_100_percent.pak" type="data_package" context="default_100_percent" />
     <output filename="ui_resources_200_percent.pak" type="data_package" context="default_200_percent" />
+    <output filename="ui_resources_300_percent.pak" type="data_package" context="default_300_percent" />
   </outputs>
   <release seq="1">
     <structures fallback_to_low_resolution="true">