The purpose is to prepare for a TextureViewRenderer that will need the
new functionality.
The new functionality is:
* Be able to create an EglRenderer using a SurfaceTexture.
* Fps reduction logic.
* Log statistics every 4 seconds regardless of framerate.
* Include swap buffer time in statistics.
* Use EglBase10 if texture frames are disabled.
* Function for printing stack trace of render thread.
* Public clearImage() function for clearing the EGLSurface.
BUG=webrtc:6470
Review-Url: https://codereview.webrtc.org/2428933002
Cr-Commit-Position: refs/heads/master@{#14698}
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