Set up field trial for expanded GPU rasterization trigger

This expands the GPU rasterization trigger for a field trial.

This depends on Blink CL http://crrev.com/309593007

BUG=380454

Review URL: https://codereview.chromium.org/314753002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275769 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/render_view_impl.cc

@@ -20,6 +20,7 @@
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/process/kill.h"
@@ -471,6 +472,11 @@ static bool ShouldUseAcceleratedFixedRootBackground(float device_scale_factor) {
   return DeviceScaleEnsuresTextQuality(device_scale_factor);
 }
 
+static bool ShouldUseExpandedHeuristicsForGpuRasterization() {
+  return base::FieldTrialList::FindFullName(
+             "GpuRasterizationExpandedContentWhitelist") == "Enabled";
+}
+
 static FaviconURL::IconType ToFaviconType(blink::WebIconURL::Type type) {
   switch (type) {
     case blink::WebIconURL::TypeFavicon:
@@ -749,6 +755,8 @@ void RenderViewImpl::Initialize(RenderViewImplParams* params) {
       ShouldUseAcceleratedFixedRootBackground(device_scale_factor_));
   webview()->settings()->setCompositedScrollingForFramesEnabled(
       ShouldUseCompositedScrollingForFrames(device_scale_factor_));
+  webview()->settings()->setUseExpandedHeuristicsForGpuRasterization(
+      ShouldUseExpandedHeuristicsForGpuRasterization());
 
   ApplyWebPreferences(webkit_preferences_, webview());