Use CheckedNumerics in AsyncPixelTransfersCompletedQuery, add tests

gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc
index 7374ffbdeaf15f6f905a48dca97ed90a29628fa2..b4dacb9da4c24d287ba2c1967ea14345fff6a929 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc
@@ -342,7 +342,9 @@ void GLES2DecoderTestBase::InitDecoderWithCommandLine(
   EXPECT_EQ(GL_NO_ERROR, GetGLError());
 }
 
-void GLES2DecoderTestBase::TearDown() {
+void GLES2DecoderTestBase::ResetDecoder() {
+  if (!decoder_.get())
+    return;
   // All Tests should have read all their GLErrors before getting here.
   EXPECT_EQ(GL_NO_ERROR, GetGLError());
 
@@ -359,6 +361,10 @@ void GLES2DecoderTestBase::TearDown() {
   gl_.reset();
 }
 
+void GLES2DecoderTestBase::TearDown() {
+  ResetDecoder();
+}
+
 void GLES2DecoderTestBase::ExpectEnableDisable(GLenum cap, bool enable) {
   if (enable) {
     EXPECT_CALL(*gl_, Enable(cap))
@@ -1418,10 +1424,12 @@ void GLES2DecoderTestBase::AddExpectationsForSimulatedAttrib0(
 
 GLES2DecoderWithShaderTestBase::MockCommandBufferEngine::
 MockCommandBufferEngine() {
-  data_.reset(new int8[kSharedBufferSize]);
-  ClearSharedMemory();
-  valid_buffer_.ptr = data_.get();
+  shm_.reset(new base::SharedMemory());
+  shm_->CreateAndMapAnonymous(kSharedBufferSize);
   valid_buffer_.size = kSharedBufferSize;
+  valid_buffer_.shared_memory = shm_.get();
+  valid_buffer_.ptr = shm_->memory();
+  ClearSharedMemory();
 }
 
 GLES2DecoderWithShaderTestBase::MockCommandBufferEngine::