Android WebView: allow for multiple target architectures.

The WebView will eventually need to be built for multiple target
architectures. Prepare for this by passing --suffix .arm to gyp when
generating the makefiles, and including an architecture-specific
makefile at the top level. Also, remove the hardcoding of arm as the
target architecture in envsetup.sh.

The previous change I made to .gitignore to only ignore *.host.mk and
*.target.mk instead of *.mk has been reverted in favour of just
specifically un-ignoring files called Android.mk (which are
handwritten).

BUG=

Review URL: https://codereview.chromium.org/11416036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168506 0039d316-1c4b-4281-b951-d872f2087c98

.gitignore

@@ -1,6 +1,6 @@
 *.Makefile
 *.gypcmd
-*.host.mk
+*.mk
 *.ncb
 *.ninja
 *.opensdf
@@ -10,7 +10,6 @@
 *.sdf
 *.sln
 *.suo
-*.target.mk
 *.targets
 *.user
 *.vcproj
@@ -24,6 +23,7 @@
 *_proto.xml
 *_proto_cpp.xml
 *~
+!Android.mk
 .*.sw?
 .DS_Store
 .classpath

Android.mk

@@ -12,7 +12,7 @@ CHROMIUM_DIR := $(call my-dir)
 
 # Assume that if the gyp autogenerated makefile exists, we are doing the
 # WebView build using the Android build system.
-ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.mk))
-include $(CHROMIUM_DIR)/GypAndroid.mk
+ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.$(TARGET_ARCH).mk))
+include $(CHROMIUM_DIR)/GypAndroid.$(TARGET_ARCH).mk
 include $(CHROMIUM_DIR)/android_webview/Android.mk
 endif

android_webview/tools/gyp_webview

@@ -13,5 +13,5 @@ set -e
 export CHROME_ANDROID_BUILD_WEBVIEW=1
 export CHROME_SRC="$(readlink -f "$(dirname "$0")/../..")"
 export PYTHONDONTWRITEBYTECODE=1
-. build/android/envsetup.sh
-android_gyp
+. build/android/envsetup.sh --target-arch=arm
+android_gyp --suffix .arm

build/android/envsetup_functions.sh

@@ -279,9 +279,6 @@ webview_build_init() {
   export ANDROID_SDK_ROOT=${ANDROID_BUILD_TOP}/prebuilts/sdk/\
 ${ANDROID_SDK_VERSION}
 
-  # For now, TARGET_ARCH is always ARM in this config.
-  TARGET_ARCH=arm
-
   common_vars_defines
 
   # We need to supply SDK paths relative to the top of the Android tree to make