Make a graph tool of dmprof useful.

1. Change the graph from bar-chart to area chat.
Now x-axis shows time line.  It is instinctive.

2. Enable to choose policies in GUI.
It is a waste of time to apply many policies and make different HTML files.
Now it can be done with clicks.  No need to specify a policy in converting json to HTML.

Usage:
$ dmprof /path/to/first.heap > temp.json
$ graph.py temp.json > graph.html  # no need to specify a poilcy
$ chrome graph.html    # open the HTML file in Chrome


BUG=None
NOTRY=true

Review URL: https://codereview.chromium.org/189623009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255764 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255764
Remove the TestContextFactory, always use NullDraw GL for unit tests.

All unit tests suites are now opted into using real NullDraw GL
contexts instead of fake "test contexts". So remove the code to
create test contexts.

Removes the --disable-test-compositor flag as this does nothing
now that no tests use test contexts.

R=sievers@chromium.org
BUG=270918

Review URL: https://codereview.chromium.org/183743014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255765 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255765