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}

1 files changed, 24 insertions, 0 deletions

diff --git a/cc/surfaces/surface_hittest_delegate.h b/cc/surfaces/surface_hittest_delegate.h
new file mode 100644
index 0000000..1f0fbf9
--- /dev/null
+++ b/cc/surfaces/surface_hittest_delegate.h
@@ -0,0 +1,24 @@
+// Copyright 2015 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.
+
+#ifndef CC_SURFACES_SURFACE_HITTEST_DELEGATE_H_
+#define CC_SURFACES_SURFACE_HITTEST_DELEGATE_H_
+
+namespace cc {
+
+class SurfaceDrawQuad;
+
+// Clients of SurfaceHittest can provide a SurfaceHittestDelegate implementation
+// to override the hit target based on metadata outside of the Surfaces system.
+class SurfaceHittestDelegate {
+ public:
+  // Return true if this delegate rejects this |surface_quad| as a candidate hit
+  // target.
+  virtual bool RejectHitTarget(const SurfaceDrawQuad* surface_quad,
+                               const gfx::Point& point_in_quad_space) = 0;
+};
+
+}  // namespace cc
+
+#endif  // CC_SURFACES_SURFACE_HITTEST_DELEGATE_H_