Add a group policy for hardware acceleration.

components/policy/resources/policy_templates.json

Index: components/policy/resources/policy_templates.json
diff --git a/components/policy/resources/policy_templates.json b/components/policy/resources/policy_templates.json
index 196aaf314a91d548b5a466d714d3c24bd09b8437..fb366ab6963a9bb24eb8ea4623b0f520b8714677 100644
--- a/components/policy/resources/policy_templates.json
+++ b/components/policy/resources/policy_templates.json
@@ -123,7 +123,7 @@
 #   persistent IDs for all fields (but not for groups!) are needed. These are
 #   specified by the 'id' keys of each policy. NEVER CHANGE EXISTING IDs,
 #   because doing so would break the deployed wire format!
-#   For your editing convenience: highest ID currently used: 302
+#   For your editing convenience: highest ID currently used: 303
 #
 # Placeholders:
 #   The following placeholder strings are automatically substituted:
@@ -3237,7 +3237,9 @@
 
       Enabling this setting prevents web pages from accessing the graphics processing unit (GPU). Specifically, web pages can not access the WebGL API and plugins can not use the Pepper 3D API.
 
-      Disabling this setting or leaving it not set potentially allows web pages to use the WebGL API and plugins to use the Pepper 3D API. The default settings of the browser may still require command line arguments to be passed in order to use these APIs.''',
+      Disabling this setting or leaving it not set potentially allows web pages to use the WebGL API and plugins to use the Pepper 3D API. The default settings of the browser may still require command line arguments to be passed in order to use these APIs.
+
+      If HardwareAccelerationModeEnabled is set to false, the Disable3DAPIs policy is forced to true.''',

[bartfab (slow), 2015/07/08 12:40:33]

Do we actually force the policy to true (i.e., will you see a value of |true|
when you visit chrome://policy), or are we just breaking the API, which has
similar/equivalent effects to setting the policy to true?

     },
     {
       'name': 'PolicyRefreshRate',
@@ -7397,6 +7399,26 @@
 
       Only if allowCorporateKeyUsage is set to true for an extension, it can use any platform key marked for corporate usage to sign arbitrary data. This permission should only be granted if the extension is trusted to secure access to the key against attackers.''',
     },
+    {
+      'name': 'HardwareAccelerationModeEnabled',
+      'type': 'main',
+      'schema': { 'type': 'boolean' },
+      'supported_on': ['chrome.*:45-'],
+      'features': {
+        'dynamic_refresh': False,
+        'per_profile': False,
+      },
+      'example_value': True,
+      'id': 303,
+      'caption': '''Use hardware acceleration when available''',
+      'desc': '''Use hardware acceleration when available.
+
+      If you enable this setting, hardware acceleration will be enabled unless a certain GPU feature is blacklisted.

[bartfab (slow), 2015/07/08 12:40:33]

Nit: As you saw with Disable3DAPIs, we (unfortunately) have some policies with
negative polarity (where *disabling* a policy *enables* a feature), leading to a
lot of confusion. We are trying to be super explicit about actual policy values
these days. Please replace "enable" with "set to true" and "disable" with "set
to false" to be 100% clear.

+
+      If you disable this setting, hardware acceleration will be disabled.
+
+      If this policy is left not set, it is equivalent to being enabled, see description above.''',
+    },
   ],
   'messages': {
     # Messages that are not associated to any policies.