Add ADPF support to WebView

The implementation is guarded by the WebViewEnableADPF feature, disabled by default.

When enabled, WebView passes the following threads to HWUI to be included in the existing ADPF session:
- GPU process: Viz, IO
- Browser process: IO
- Renderer process: Compositor, IO

Additionally, when the WebViewEnableADPFRendererMain feature is enabled, the Renderer Main thread is also reported to HWUI.

The threads from GPU and Browser process are trusted, and reported unconditionally. The threads from the Renderer process are not trusted and verified not to belong to the GPU or Browser process - this is the same as in the Chrome app.

The design doc (+ the HWUI-side CLs) are attached to the bug.

Testing: local tests with WebViewEnableADPF/WebViewEnableADPFRendererMain show a correct list of threads passed to `AwDrawFnImpl::ReportRenderingThreads` (based on debug logging) in a couple of different Android apps that use WebView.

Change-Id: I13d6724b5e9244558881aa7b4bcae312820b9354

Bug: b/329219352
Change-Id: I13d6724b5e9244558881aa7b4bcae312820b9354
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5344690


Reviewed-by: Eric Seckler <eseckler@chromium.org>
Commit-Queue: Igor Kraskevich <kraskevich@google.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Richard (Torne) Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1281827}