Roll chromium_revision a12e1e1..0cb2549 (326495:327252)

https://codereview.chromium.org/1051343002 adds a dependency
on Chromium's third_party/junit into base/ which affects our
Android tests that uses that code.

The precompiled JUnit 4.11 JAR file that is only by the
libjingle_peerconnection_java_unittest target on Linux has been
moved to third_party/junit-jar, since it collided with the expected
path for the JUnit dependency mentioned above.
It had to be kept since the Chromium JUnit is only possible to build
when OS==android.

This CL also brings in Mockito and Robolectric, which should be
useful for our Android tests.

Other relevant changes:
* src/buildtools: 3b302fe..15308f4
* src/third_party/libjpeg_turbo: 034e9a9..9e9058b
* src/third_party/libyuv: 32ad6e0..01db3d1
Details: a12e1e1..0cb2549/DEPS

Clang version was not updated in this roll.

BUG=4499
R=phoglund@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/48239004

Cr-Commit-Position: refs/heads/master@{#9113}

sync_chromium.py

@@ -30,7 +30,7 @@ import textwrap
 
 # Bump this whenever the algorithm changes and you need bots/devs to re-sync,
 # ignoring the .last_sync_chromium file
-SCRIPT_VERSION = 4
+SCRIPT_VERSION = 5
 
 ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
 CHROMIUM_NO_HISTORY = 'CHROMIUM_NO_HISTORY'