Take SupportsSeparateFramebufferBinds into account in ClearLevelUsingGL

Query SupportsSeparateFramebufferBinds to determine if the framebuffer
target should be GL_DRAW_FRAMEBUFFER_EXT or GL_FRAMEBUFFER_EXT.

Update tests so that one test uses an ES2 context and tests target
GL_FRAMEBUFFER_EXT, while the other test uses an ES3 context and tests
target GL_DRAW_FRAMEBUFFER_EXT.

Bug: 848952
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: If9ff227498e10aef912f38e7bc26700c7513ed87
Reviewed-on: https://chromium-review.googlesource.com/1165597
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#581312}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9e1dd1485923316a9fcee03891706263a8c148bc
2 files changed