Unit tests have been created for the GPUTiming.

ui/gl/gpu_timing_fake.h

Index: ui/gl/gpu_timing_fake.h
diff --git a/ui/gl/gpu_timing_fake.h b/ui/gl/gpu_timing_fake.h
new file mode 100644
index 0000000000000000000000000000000000000000..932f162cd5395570e99f4552f5f615945c25a112
--- /dev/null
+++ b/ui/gl/gpu_timing_fake.h
@@ -0,0 +1,82 @@
+// 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 UI_GL_GPU_TIMING_FAKE_H_
+#define UI_GL_GPU_TIMING_FAKE_H_
+
+#include <map>
+#include <set>
+
+#include "ui/gl/gl_bindings.h"
+
+namespace gfx {
+class MockGLInterface;
+
+class GPUTimingFakeGLQueries {

[no sievers, 2015/06/09 22:56:41]

Can you make the class name match the file name?

[David Yen, 2015/06/09 23:04:24]

Done.

+ public:
+  GPUTimingFakeGLQueries();
+  ~GPUTimingFakeGLQueries();
+
+  void Reset();
+
+  // Used to set the current GPU time queries will return.
+  void SetCurrentGLTime(GLint64 current_time);
+
+  // Used to signal a disjoint occurred for disjoint timer queries.
+  void SetDisjoint();
+
+  // GPUTimer fake queries which can be called multiple times.
+  void ExpectGetErrorCalls(MockGLInterface& gl);
+  void ExpectDisjointCalls(MockGLInterface& gl);
+  void ExpectNoDisjointCalls(MockGLInterface& gl);
+
+  // GPUTimer fake queries which can only be called once per setup.
+  void ExpectGPUTimerQuery(MockGLInterface& gl, bool elapsed_query);
+  void ExpectOffsetCalculationQuery(MockGLInterface& gl);
+  void ExpectNoOffsetCalculationQuery(MockGLInterface& gl);
+
+  // Fake GL Functions.
+  void FakeGLGenQueries(GLsizei n, GLuint* ids);
+  void FakeGLDeleteQueries(GLsizei n, const GLuint* ids);
+  void FakeGLBeginQuery(GLenum target, GLuint id);
+  void FakeGLEndQuery(GLenum target);
+  void FakeGLGetQueryObjectiv(GLuint id, GLenum pname, GLint* params);
+  void FakeGLQueryCounter(GLuint id, GLenum target);
+  void FakeGLGetInteger64v(GLenum pname, GLint64 * data);
+  void FakeGLGetQueryObjectui64v(GLuint id, GLenum pname, GLuint64* params);
+  void FakeGLGetIntegerv(GLenum pname, GLint* params);
+  GLenum FakeGLGetError();
+
+ protected:
+  bool disjointed_ = false;
+  GLint64 current_time_ = 0;
+  GLuint next_query_id_ = 0;
+  std::set<GLuint> allocated_queries_;
+  struct QueryResult {
+    enum QueryResultType {
+      kQueryResultType_Invalid,
+      kQueryResultType_TimeStamp,
+      kQueryResultType_Elapsed
+    } type_ = kQueryResultType_Invalid;
+    GLint64 begin_time_ = 0;
+    GLint64 value_ = 0;
+  };
+  std::map<GLuint, QueryResult> query_results_;
+  struct ElapsedQuery {
+    bool active_ = false;
+    GLuint query_id_ = 0;
+    GLint64 begin_time_ = 0;
+
+    void Reset() {
+      active_ = false;
+      query_id_ = 0;
+      begin_time_ = 0;
+    }
+  };
+  ElapsedQuery current_elapsed_query_;
+};
+
+}  // namespace gfx
+
+#endif  // UI_GL_GPU_TIMING_FAKE_H_