android: Fold all_android.gyp into all.gyp.

build/android/envsetup_functions.sh

Index: build/android/envsetup_functions.sh
diff --git a/build/android/envsetup_functions.sh b/build/android/envsetup_functions.sh
index af241163d520b0771dc5bc4b744d85a7c724f0e0..228d0315e9095a54f429b05ce3ef73cc4bf4dcc1 100755
--- a/build/android/envsetup_functions.sh
+++ b/build/android/envsetup_functions.sh
@@ -146,8 +146,11 @@ common_gyp_vars() {
   # Use our All target as the default
   export GYP_GENERATOR_FLAGS="${GYP_GENERATOR_FLAGS} default_target=All"
 
-  # We want to use our version of "all" targets.
-  export CHROMIUM_GYP_FILE="${CHROME_SRC}/build/all_android.gyp"
+  # TODO(thakis): Remove this after a week or two. Sourcing envsetup.sh used to
+  # set this variable, but now that all_android.gyp is gone having it set will
+  # lead to errors, so explicitly unset it to remove it from the environment of
+  # developers who keep their shells open for weeks (most of them, probably).
+  unset CHROMIUM_GYP_FILE
 }