Defer compositor context creation to the thread.

cc/test/test_web_graphics_context_3d.h

Index: cc/test/test_web_graphics_context_3d.h
diff --git a/cc/test/test_web_graphics_context_3d.h b/cc/test/test_web_graphics_context_3d.h
index d37ef51e70dbd38b470e23ba46dbef71e65a3b76..2cfadfe585f6338f38d35708381b425c16987554 100644
--- a/cc/test/test_web_graphics_context_3d.h
+++ b/cc/test/test_web_graphics_context_3d.h
@@ -310,6 +310,11 @@ class TestWebGraphicsContext3D {
   }
   void ResetUsedTextures() { used_textures_.clear(); }
 
+  void set_capabilities(const gpu::Capabilities& caps) {
+    test_capabilities_ = caps;
+    test_capabilities_.image = true;
+  }
+
   void set_have_extension_io_surface(bool have) {
     test_capabilities_.iosurface = have;
     test_capabilities_.texture_rectangle = have;
@@ -341,7 +346,6 @@ class TestWebGraphicsContext3D {
   void set_support_sync_query(bool support) {
     test_capabilities_.sync_query = support;
   }
-  void set_support_image(bool support) { test_capabilities_.image = support; }
   void set_support_texture_rectangle(bool support) {
     test_capabilities_.texture_rectangle = support;
   }
@@ -351,6 +355,9 @@ class TestWebGraphicsContext3D {
   void set_msaa_is_slow(bool msaa_is_slow) {
     test_capabilities_.msaa_is_slow = msaa_is_slow;
   }
+  void set_max_samples(int max_samples) {
+    test_capabilities_.max_samples = max_samples;
+  }
 
   // When this context is lost, all contexts in its share group are also lost.
   void add_share_group_context(TestWebGraphicsContext3D* context3d) {
@@ -375,7 +382,6 @@ class TestWebGraphicsContext3D {
   virtual GLuint NextRenderbufferId();
   virtual void RetireRenderbufferId(GLuint id);
 
-  void SetMaxSamples(int max_samples);
   void set_test_support(TestContextSupport* test_support) {
     test_support_ = test_support;
   }