Add platform/prebuilts/android-emulator

Change-Id: I986ca0e19ca3e2d96c9985bdefc8482e271a4864
Update manifest for latest external/chromium_org.

Bring the chromium_org projects in sync with the latest version.

Change-Id: Iffefd8539530b58255153fac40e5b92cefa11312
Add host prebuilts for Clang 3.5.

Change-Id: I2e2a3f921e67e972ef9962257ef80903780a031b
Move to glibc2.11-4.6 and add missing libcxx-related projects to the manifest.

Change-Id: I6c8a2b228ff5f59227fca9674ef883ce6fd8e631