Reason for revert: Trying to re-land after solving some related issues. There are no changes compared to the original CL. Original issue's description: > Revert of Loosening the coupling between WebRTC and //third_party/protobuf (patchset #16 id:300001 of https://codereview.webrtc.org/2747863003/ ) > > Reason for revert: > I will try to reland next week because it is causing some problems. > > Original issue's description: > > To accommodate some downstream WebRTC users we need to loosen > > the coupling between our code and the //third_party/protobuf. > > > > This includes using typedefs to define strings instead of > > assuming std::string. > > > > After this refactoring it will be possible to link with other > > protobuf implementations than the current one. > > > > We moved the PRESUBMIT check to another CL [1]. The goal of this > > presubmit is to avoid the direct usage of google::protobuf outside > > of the webrtc/base/protobuf_utils.h header file. > > > > [1] - https://codereview.webrtc.org/2753823003/ > > > > BUG=webrtc:7340 > > NOTRY=True > > > > Review-Url: https://codereview.webrtc.org/2747863003 > > Cr-Commit-Position: refs/heads/master@{#17466} > > Committed:16ab93b952> > TBR=kjellander@webrtc.org,henrik.lundin@webrtc.org,kwiberg@webrtc.org,michaelt@webrtc.org,peah@webrtc.org > # Not skipping CQ checks because original CL landed more than 1 days ago. > BUG=webrtc:7340 > > Review-Url: https://codereview.webrtc.org/2786363002 > Cr-Commit-Position: refs/heads/master@{#17483} > Committed:d00aad5eb2TBR=kjellander@webrtc.org,henrik.lundin@webrtc.org,kwiberg@webrtc.org,michaelt@webrtc.org,peah@webrtc.org # Not skipping CQ checks because original CL landed more than 1 days ago. BUG=webrtc:7340 NOTRY=True Review-Url: https://codereview.webrtc.org/2791963003 Cr-Commit-Position: refs/heads/master@{#17584}