BKM for Rebasing chromium crosswalk

Rebase master branch

• Backup current master:
• Create a new branch named master_history_<chromium version>, e.g. master_history_28_0_1500_36.
• Push it to chromium-crosswalk repo.
• Decide new upstream base:
• Choose the latest beta channel version from http://omahaproxy.appspot.com/.
• Prepare upstream git for chosen version:
• Upstream only maintain trunk in its git repo.
• Need to use git-svn to fetch the commits after upstream branches from trunk.
• BKM reference
• Do rebasing:
• Use rebase -i to only pick our commits.
• Verify content shell build locally.
• Force update master.
• Update buildbot/trybot content shell slaves' config
• Inform @wang16 or @halton, no automatic solution currently.
• Verify Crosswalk build locally.
• Send pull request to Crosswalk master, the pull request should include:
• The fix to make Crosswalk work with new based chromium-crosswalk.
• Update DEPS.crosswalk for version and commit hash.

Rebase Release branch

• Basically same as master branch's rebase. Following are the differences:
• Backup branch should be named <release branch name>_history_<chromium version>, e.g. release_v1.0_history_28_0_1500_36
• When choosing new base, choose the latest patch update for current release, e.g. 28_0_1500_80 for 28_0_1500_36.
• Force update release branch in chromium-crosswalk after rebase.
• Send pull request to the corresponding branch in crosswalk.

Prepare upstream specified version's git tree

• Constructing...