[android] Roll to the Android O SDK.

Bug: 735481
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester
Change-Id: Id0a424f4460f7ea3ed88991ec689a779b501f2b9
Reviewed-on: https://chromium-review.googlesource.com/550924
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Helen Li <xunjieli@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#483105}

• DEPS[diff]
• build/android/pylib/constants/__init__.py[diff]
• build/config/android/config.gni[diff]
• chrome/android/BUILD.gn[diff]
• chrome/android/javatests/src/org/chromium/chrome/browser/crash/LogcatExtractionRunnableTest.java[diff]
• chrome/android/javatests/src/org/chromium/chrome/browser/crash/MinidumpUploadServiceTest.java[diff]
• components/cronet/android/api/build.xml[diff]