Copy quad rect when replacing overlay quad.

Previously, RenderPass::Replace...Color() was taking a reference
to the quad's rectangle, then replacing the quad.  Unfortunately,
that destroys the original rect before it can be re-used a few
lines later.

This CL just makes a copy of the rect instead.

BUG=751746

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ice4a5e147000813a1e19c60ba33de5f36b2b11d7
Reviewed-on: https://chromium-review.googlesource.com/598489
Commit-Queue: Frank Liberato <liberato@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491764}

cc/quads/render_pass.cc

@@ -51,16 +51,15 @@ void QuadList::ReplaceExistingQuadWithOpaqueTransparentSolidColor(Iterator at) {
   // solid color quad needs to set |needs_blending| to false, and set both
   // |visible_rect| and |opaque_rect| to its quad rect so it is drawn and
   // ShouldDrawWithBlending() returns false so it is drawn without blending.
-  const gfx::Rect& rect = at->rect;
-  const gfx::Rect& opaque_rect = at->rect;
-  const gfx::Rect& visible_rect = at->rect;
+  const gfx::Rect rect = at->rect;
   bool needs_blending = false;
   const SharedQuadState* shared_quad_state = at->shared_quad_state;
 
   SolidColorDrawQuad* replacement =
       QuadList::ReplaceExistingElement<SolidColorDrawQuad>(at);
-  replacement->SetAll(shared_quad_state, rect, opaque_rect, visible_rect,
-                      needs_blending, SK_ColorTRANSPARENT, true);
+  replacement->SetAll(shared_quad_state, rect, rect /* opaque_rect */,
+                      rect /* visible_rect */, needs_blending,
+                      SK_ColorTRANSPARENT, true);
 }
 
 std::unique_ptr<RenderPass> RenderPass::Create() {

cc/quads/render_pass_unittest.cc

@@ -288,5 +288,18 @@ TEST(RenderPassTest, CopyAllWithCulledQuads) {
   CompareRenderPassLists(pass_list, copy_list);
 }
 
+TEST(RenderPassTest, ReplacedQuadsShouldntMove) {
+  std::unique_ptr<SharedQuadState> quad_state =
+      base::MakeUnique<SharedQuadState>();
+  QuadList quad_list;
+  SolidColorDrawQuad* quad =
+      quad_list.AllocateAndConstruct<SolidColorDrawQuad>();
+  gfx::Rect quad_rect(1, 2, 3, 4);
+  quad->SetNew(quad_state.get(), quad_rect, quad_rect, SkColor(), false);
+  quad_list.ReplaceExistingQuadWithOpaqueTransparentSolidColor(
+      quad_list.begin());
+  EXPECT_EQ(quad_list.begin()->rect, quad_rect);
+}
+
 }  // namespace
 }  // namespace cc