Some comments and questions around android Surface with GPU process.

• [1] GeckoProcessManager needs to create GPU process
  • https://github.com/sotaroikeda/firefox-diagrams/blob/master/mobile/mobile_GeckoProcessManager_68.pdf
• [2] Move SurfaceAllocatorService to GPU process
  • GonkSurface is used for WebGL and video decoding by MediaDecoder.
  • SurfaceAllocatorService allocates SurfaceTexture(BufferQueue/GLConsumer) in a process that the SurfaceAllocatorService exists.
  • Then it nees to be created in a process that Compositor/WebRender exists.
  • SurfaceTexture is used to bind to GL texture to SurfaceTexture. android Surface just owns buffer produder. SurfaceTexture is buffer consumer(GLConsumer).
  • https://github.com/sotaroikeda/firefox-diagrams/blob/master/mobile/mobile_SurfaceAllocatorService_68.pdf
  • https://github.com/sotaroikeda/firefox-diagrams/blob/master/mobile/mobile_CodecProxy_68.pdf
  • https://github.com/sotaroikeda/android-diagrams/blob/master/graphics/ANativeWindow_5.0.pdf
• [3] Android surface of SurfaceView needs to be delivered from Parent process to GPU process via android Binder ipc.
  • Compositor/WebRender create EGLSurface from the Surface and do rendering to it.
  • https://github.com/sotaroikeda/firefox-diagrams/blob/master/mobile/mobile_GeckoSession_68.pdf
• [4] Needs to enable SharedSurface_SurfaceTexture in GPU process.
  • SharedSurface_SurfaceTexture is disabled for now even in content process(Bug 1654459) since Bug 1632249[WebGL compositing refactor (for out-of-process)].
  • It is necessary for performance.
• [5] How to implement video frame upload to WebGL?
  • GonkSurface is used for video decoding. SurfaceTexture of GonkSurface does not exist in content process.
  • Then current implementation allocates copyback SurfaceTexture in content process and copyback the content to content process.
  • If GPU process WebGL is enabled, it might not necessary to use copyback SurfaceTexture.
  • But SurfaceTexture has a limination. It could bind to one GL context at a time.
  • https://github.com/sotaroikeda/firefox-diagrams/blob/master/mobile/mobile_SurfaceAllocatorService_68.pdf
• [6] How to handle readback of WebGL in content process?
  • I do not know how current GPU process WebGL handles it. It seems necessary when BasicLayerMnager is used in content process.
• [7] Do we need to add support of readback of decoded video?
  • current gecko does not support it because of surface texture limitation.
• [8] We might need to think about merging GPU process and MediaManager(:media) process for reducing memory usage.

Adding bug 1749745 as blocking, as occasionally it results in a freeze following a GPU process restart

https://hg.mozilla.org/mozilla-central/rev/f93a4ff5c045

Backed out for causing Bug 1644486.

Backed out as requested: https://hg.mozilla.org/integration/autoland/rev/3e7157dac2f87609f75ae4cb2a3177e13737b6c5

Backout has been merged to central

We noticed a regression around the time the GPU process was introduced which went away when the GPU process was disabled so I filed bug 1756700 to address that.

Backed out on @Jamie's request

Backout link: https://hg.mozilla.org/integration/autoland/rev/aef9bc4794550cde08b11fad57c5c0c7ea87ac47

https://hg.mozilla.org/mozilla-central/rev/39c1f452042d

Moving GPU process bugs to the new GeckoView::Sandboxing component.