cc: Allow Surfaces clients to customize hit testing

Until we have a better hit testing data structure based on
slimming paint work, Mus needs to annotate surfaces hit
testing with additional information for shadows.

This CL provides a generic customization hook to allow a
Surfaces client to make a hit testing decision based on
factors unknown to cc.

Note that this is a short term solution until we have a
better hit testing data structure from slimming paint.

BUG=548424
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1503553002

Cr-Commit-Position: refs/heads/master@{#363371}

2 files changed, 53 insertions, 0 deletions

diff --git a/cc/test/surface_hittest_test_helpers.cc b/cc/test/surface_hittest_test_helpers.cc
index 8c57959..b83d6d4 100644
--- a/cc/test/surface_hittest_test_helpers.cc
+++ b/cc/test/surface_hittest_test_helpers.cc
@@ -92,5 +92,32 @@ scoped_ptr<CompositorFrame> CreateCompositorFrame(const gfx::Rect& root_rect,
   return root_frame;
 }
 
+TestSurfaceHittestDelegate::TestSurfaceHittestDelegate()
+    : target_overrides_(0) {}
+
+TestSurfaceHittestDelegate::~TestSurfaceHittestDelegate() {}
+
+void TestSurfaceHittestDelegate::AddInsetsForSurface(
+    const SurfaceId& surface_id,
+    const gfx::Insets& inset) {
+  insets_for_surface_.insert(std::make_pair(surface_id, inset));
+}
+
+bool TestSurfaceHittestDelegate::RejectHitTarget(
+    const SurfaceDrawQuad* surface_quad,
+    const gfx::Point& point_in_quad_space) {
+  if (!insets_for_surface_.count(surface_quad->surface_id))
+    return false;
+  gfx::Rect bounds(surface_quad->rect);
+  bounds.Inset(insets_for_surface_[surface_quad->surface_id]);
+  // If the point provided falls outside the inset, then we skip this surface.
+  if (!bounds.Contains(point_in_quad_space)) {
+    if (surface_quad->rect.Contains(point_in_quad_space))
+      ++target_overrides_;
+    return true;
+  }
+  return false;
+}
+
 }  // namespace test
 }  // namespace cc
diff --git a/cc/test/surface_hittest_test_helpers.h b/cc/test/surface_hittest_test_helpers.h
index be4ad2e..4a27659 100644
--- a/cc/test/surface_hittest_test_helpers.h
+++ b/cc/test/surface_hittest_test_helpers.h
@@ -5,9 +5,14 @@
 #ifndef CC_TEST_SURFACE_HITTEST_TEST_HELPERS_H_
 #define CC_TEST_SURFACE_HITTEST_TEST_HELPERS_H_
 
+#include <map>
+
+#include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/quads/render_pass.h"
 #include "cc/surfaces/surface_factory_client.h"
+#include "cc/surfaces/surface_hittest_delegate.h"
+#include "ui/gfx/geometry/insets.h"
 
 namespace gfx {
 class Transform;
@@ -60,6 +65,27 @@ scoped_ptr<CompositorFrame> CreateCompositorFrameWithRenderPassList(
 scoped_ptr<CompositorFrame> CreateCompositorFrame(const gfx::Rect& root_rect,
                                                   RenderPass** render_pass);
 
+class TestSurfaceHittestDelegate : public SurfaceHittestDelegate {
+ public:
+  TestSurfaceHittestDelegate();
+  ~TestSurfaceHittestDelegate();
+
+  int target_overrides() const { return target_overrides_; }
+
+  void AddInsetsForSurface(const SurfaceId& surface_id,
+                           const gfx::Insets& inset);
+
+  // SurfaceHittestDelegate implementation.
+  bool RejectHitTarget(const SurfaceDrawQuad* surface_quad,
+                       const gfx::Point& point_in_quad_space) override;
+
+ private:
+  int target_overrides_;
+  std::map<SurfaceId, gfx::Insets> insets_for_surface_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestSurfaceHittestDelegate);
+};
+
 }  // namespace test
 }  // namespace cc