Prepare WebGL contexts for resource sharing with the compositor context.

webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc

Index: webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc
===================================================================
--- webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc	(revision 102813)
+++ webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc	(working copy)
@@ -590,14 +590,6 @@
   g_all_shared_contexts.Pointer()->erase(this);
 }
 
-// This string should only be passed for WebGL contexts. Nothing ELSE!!!
-// Compositor contexts, Canvas2D contexts, Pepper Contexts, nor any other use of
-// a context should not pass this string.
-static const char* kWebGLPreferredGLExtensions =
-    "GL_OES_packed_depth_stencil "
-    "GL_OES_depth24 "
-    "GL_CHROMIUM_webglsl";
-
 bool WebGraphicsContext3DInProcessCommandBufferImpl::initialize(
     WebGraphicsContext3D::Attributes attributes,
     WebKit::WebView* web_view,
@@ -619,8 +611,7 @@
     GLInProcessContext::NONE,
   };
 
-  const char* preferred_extensions = attributes.noExtensions ?
-      kWebGLPreferredGLExtensions : "*";
+  const char* preferred_extensions = "*";
 
   GURL active_url;
   if (web_view && web_view->mainFrame())
@@ -656,6 +647,10 @@
     return false;
 
   gl_ = context_->GetImplementation();
+
+  if (gl_ && attributes.noExtensions)
+    gl_->EnableFeatureCHROMIUM("webgl_enable_glsl_webgl_validation");
+
   context_->SetContextLostCallback(
       NewCallback(
           this,