Merge third_party/mesa/src from https://chromium.googlesource.com/chromium/deps/mesa.git at 2a3406721cd61852bebd502c7a907cf07b7be731

This commit was generated by merge_from_chromium.py.

Change-Id: Ida738bc5247e9b01dba5ad3be523c4a4eb1e6ddf