Fix DCHECK to not fire on initialize failure

Also add some new tests to verify Initialize() failures.

BUG=883620
TEST=new tests pass

Change-Id: I8ed3ca04b37fcdca4b9c9c3483b1d7c696bf232a
Reviewed-on: https://chromium-review.googlesource.com/c/1336059Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608122}

media/mojo/services/mojo_video_decoder_service.cc

@@ -269,7 +269,7 @@ void MojoVideoDecoderService::Reset(ResetCallback callback) {
 
 void MojoVideoDecoderService::OnDecoderInitialized(bool success) {
   DVLOG(1) << __func__;
-  DCHECK(decoder_);
+  DCHECK(!success || decoder_);
   DCHECK(init_cb_);
   TRACE_EVENT_ASYNC_END1("media", kInitializeTraceName, this, "success",
                          success);

media/mojo/test/mojo_video_decoder_integration_test.cc

@@ -325,6 +325,32 @@ TEST_F(MojoVideoDecoderIntegrationTest, Initialize) {
   EXPECT_EQ(client_->GetMaxDecodeRequests(), kMaxDecodeRequests);
 }
 
+TEST_F(MojoVideoDecoderIntegrationTest, InitializeFailNoDecoder) {
+  CreateClient();
+
+  StrictMock<base::MockCallback<VideoDecoder::InitCB>> init_cb;
+  EXPECT_CALL(init_cb, Run(false));
+
+  // Clear |decoder_| so that Initialize() should fail.
+  decoder_.reset();
+  client_->Initialize(TestVideoConfig::NormalH264(), false, nullptr,
+                      init_cb.Get(), output_cb_.Get(), base::NullCallback());
+  RunUntilIdle();
+}
+
+TEST_F(MojoVideoDecoderIntegrationTest, InitializeFailNoCdm) {
+  CreateClient();
+
+  StrictMock<base::MockCallback<VideoDecoder::InitCB>> init_cb;
+  EXPECT_CALL(init_cb, Run(false));
+
+  // CdmContext* (3rd parameter) is not provided but the VideoDecoderConfig
+  // specifies encrypted video, so Initialize() should fail.
+  client_->Initialize(TestVideoConfig::NormalEncrypted(), false, nullptr,
+                      init_cb.Get(), output_cb_.Get(), base::NullCallback());
+  RunUntilIdle();
+}
+
 TEST_F(MojoVideoDecoderIntegrationTest, MediaLogIsProxied) {
   ASSERT_TRUE(Initialize());
   EXPECT_MEDIA_LOG_ON(client_media_log_, HasSubstr("\"test\""));