Implement mix-blend-mode in GL renderer using shaders.

cc/test/render_pass_test_utils.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/test/render_pass_test_utils.h"
 
 #include "cc/quads/render_pass_draw_quad.h"
 #include "cc/quads/shared_quad_state.h"
 #include "cc/quads/solid_color_draw_quad.h"
 #include "cc/resources/resource_provider.h"
@@ skipping 92 matching lines @@
                gfx::RectF(),
                FilterOperations(),
                gfx::Vector2dF(),
                FilterOperations());
 }
 
 void AddRenderPassQuad(TestRenderPass* to_pass,
                        TestRenderPass* contributing_pass,
                        ResourceProvider::ResourceId mask_resource_id,
                        const FilterOperations& filters,
-                       gfx::Transform transform) {
+                       gfx::Transform transform,
+                       SkXfermode::Mode blend_mode) {
   gfx::Rect output_rect = contributing_pass->output_rect;
   SharedQuadState* shared_state = to_pass->CreateAndAppendSharedQuadState();
   shared_state->SetAll(transform,
                        output_rect.size(),
                        output_rect,
                        output_rect,
                        false,
                        1,
-                       SkXfermode::kSrcOver_Mode,
+                       blend_mode,
                        0);
   RenderPassDrawQuad* quad =
       to_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
   quad->SetNew(shared_state,
                output_rect,
                output_rect,
                contributing_pass->id,
                mask_resource_id,
                gfx::RectF(),
                filters,
                gfx::Vector2dF(),
                FilterOperations());
 }
 
 }  // namespace cc