Simplify "WouldTaintOrigin" concept in media/blink

Currently WebMediaPlayer has three predicates:
 - DidGetOpaqueResponseFromServiceWorker
 - HasSingleSecurityOrigin
 - DidPassCORSAccessCheck
. These are used to determine whether the response body is available
for scripts. They are known to be confusing, and actually
MediaElementAudioSourceHandler::WouldTaintOrigin misuses them.

This CL merges the three predicates to one, WouldTaintOrigin, to remove
the confusion. Now the "response type" concept is available and we
don't need a custom CORS check, so this CL removes
BaseAudioContext::WouldTaintOrigin. This CL also renames
URLData::has_opaque_data_ and its (direct and indirect) data accessors
to match the spec.

Bug: 849942, 875153
Change-Id: I6acf50169d7445c4ff614e80ac606f79ee577d2a
Reviewed-on: https://chromium-review.googlesource.com/c/1238098
Reviewed-by: Fredrik Hubinette <hubbe@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Raymond Toy <rtoy@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598258}
  void InitializeWithCORS(const char* url,
                          bool expected,
                          UrlData::CORSMode cors_mode,
                          size_t file_size = kFileSize) {
    GURL gurl(url);
    data_source_.reset(new MockMultibufferDataSource(
        base::ThreadTaskRunnerHandle::Get(),
        url_index_->GetByUrl(gurl, cors_mode), &host_));
    data_source_->SetPreload(preload_);

    response_generator_.reset(new TestResponseGenerator(gurl, file_size));
    EXPECT_CALL(*this, OnInitialize(expected));
    data_source_->Initialize(base::Bind(
        &MultibufferDataSourceTest::OnInitialize, base::Unretained(this)));
    base::RunLoop().RunUntilIdle();

    EXPECT_EQ(data_source_->downloading(), false);
  }

  void InitializeWithCORS(const char* url,
                          bool expected,
                          UrlData::CORSMode cors_mode,
                          size_t file_size = kFileSize) {
    GURL gurl(url);
    data_source_.reset(new MockMultibufferDataSource(
        base::ThreadTaskRunnerHandle::Get(),
        url_index_->GetByUrl(gurl, cors_mode), &host_));
    data_source_->SetPreload(preload_);

    response_generator_.reset(new TestResponseGenerator(gurl, file_size));
    EXPECT_CALL(*this, OnInitialize(expected));
    data_source_->Initialize(base::Bind(
        &MultibufferDataSourceTest::OnInitialize, base::Unretained(this)));
    base::RunLoop().RunUntilIdle();

    EXPECT_EQ(data_source_->downloading(), false);
  }
