Set fPreferExternalImagesOverES3 to true.

Set GrContextOptions::fPreferExternalImagesOverES3 to true
which causes Skia to use ES2 instead of ES3 if
GL_OES_EGL_image_external_essl3 is not available and
GL_OES_EGL_image_external is available.

Bug: 1031383,1104891
Change-Id: I87c2e35e4f1ae95a4882a275d3aceb416c47bd0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2296875Reviewed-by: Khushal <khushalsagar@chromium.org>
Commit-Queue: vikas soni <vikassoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788507}

gpu/command_buffer/service/shared_context_state.cc

@@ -265,6 +265,7 @@ bool SharedContextState::InitializeGrContext(
     options.fShaderErrorHandler = this;
     if (gpu_preferences.force_max_texture_size)
       options.fMaxTextureSizeOverride = gpu_preferences.force_max_texture_size;
+    options.fPreferExternalImagesOverES3 = true;
     owned_gr_context_ = GrContext::MakeGL(std::move(interface), options);
     gr_context_ = owned_gr_context_.get();
   }