Expose WebGL extension WEBGL_debug_renderer_info to Google domains

content/browser/gpu/gpu_data_manager_impl_private.cc

Index: content/browser/gpu/gpu_data_manager_impl_private.cc
diff --git a/content/browser/gpu/gpu_data_manager_impl_private.cc b/content/browser/gpu/gpu_data_manager_impl_private.cc
index ab8029c63b925b6e481a48f346bde38809a53106..56b8f27578acf562ed8d4b7b526cd4fdf2045405 100644
--- a/content/browser/gpu/gpu_data_manager_impl_private.cc
+++ b/content/browser/gpu/gpu_data_manager_impl_private.cc
@@ -19,6 +19,7 @@
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/gpu_data_manager_observer.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_constants.h"
@@ -312,6 +313,17 @@ enum BlockStatusHistogram {
   BLOCK_STATUS_MAX
 };
 
+bool IsWebGLDebugRendererInfoFieldTrialEnabled() {
+  const char kWebGLDebugRendererInfoFieldTrialName[] = "WebGLDebugRendererInfo";
+  const char kWebGLDebugRendererInfoFieldTrialEnabledName[] = "enabled";
+
+  base::FieldTrial* trial = base::FieldTrialList::Find(
+      kWebGLDebugRendererInfoFieldTrialName);
+  if (!trial)
+    return false;
+  return trial->group_name() == kWebGLDebugRendererInfoFieldTrialEnabledName;

[Alexei Svitkine (slow), 2013/10/30 18:10:18]

Instead, just use base::FieldTrialList::FindFullName() and just compare it to
kWebGLDebugRendererInfoFieldTrialEnabledName.

(If there's no trial, an empty string is returned.)

[Zhenyao Mo, 2013/10/30 20:20:50]

Done.

See chrome_render_message_filter.cc

+}
+
 }  // namespace anonymous
 
 void GpuDataManagerImplPrivate::InitializeForTesting(
@@ -1259,6 +1271,22 @@ void GpuDataManagerImplPrivate::Notify3DAPIBlocked(const GURL& url,
                          url, render_process_id, render_view_id, requester);
 }
 
+bool GpuDataManagerImplPrivate::IsWebGLDebugRendererInfoAllowed(
+    const GURL& url) const {
+  const CommandLine* command_line = CommandLine::ForCurrentProcess();
+  // Allow someone to disable this extension in WebGL.
+  if (command_line->HasSwitch(switches::kDisableWebGLDebugRendererInfo))
+    return false;
+  // Allow someone to force-enable this extension. This is mostly for
+  // testing purpose.
+  if (command_line->HasSwitch(switches::kEnableWebGLDebugRendererInfo))
+    return true;

[Ken Russell (switch to Gerrit), 2013/10/29 23:15:35]

The test of the kEnableWebGLDebugRendererInfo switch should be moved after the
AllowWebGLDebugRendererInfoForDomain call below so that
ChromeContentBrowserClient::AllowWebGLDebugRendererInfoForDomain can be tested
too (using the kGoogleBaseURL flag).

[Zhenyao Mo, 2013/10/29 23:33:43]

I just realized we can probably get rid of the kEnableWebGLDebugRendererInfo
switch, because we can use --force-fieldtrials combined with --google-base-url
to get this function to return true/false in all possible scenarios.  So
kEnableWebGLdebugRendererInfo doesn't need to be used in tests to emulate any
scenarios.

Also, it seems like finch has a mechanism to automatically insert a flag in
about:flags to let users opt in/out, so probably we don't need the
kDisableWebGLDebugRendererInfo switch also.

What do you think?

[Zhenyao Mo, 2013/10/29 23:43:37]

Never mind about this auto flag thing.  I read the documents more carefully, and
it's not what I thought it was.  We still need the disable- flag here.

[Ken Russell (switch to Gerrit), 2013/10/29 23:58:16]

OK. Using --force-fieldtrials and removing the kEnableWebGLDebugRendererInfo
switch sounds like a good plan.

+
+  if (!GetContentClient()->browser()->AllowWebGLDebugRendererInfoForDomain(url))
+    return false;
+  return IsWebGLDebugRendererInfoFieldTrialEnabled();
+}
+
 void GpuDataManagerImplPrivate::OnGpuProcessInitFailure() {
   gpu_process_accessible_ = false;
   gpu_info_.finalized = true;