Android: Default to Android Studio's SDK

Enabling the default as per: https://crrev.com/c/1058308

Obviates the need to pass in `--sdk AndroidStudioDefault` and making
local edits to //third_party/android_tools/sdk when updating the sdk.

Update docs so that using the `gradle` folder when importing is more
prominent.

Bug: 620034,843264
Change-Id: I3c3c56a7d15b57ce0aaa9d4029493dc574045ceb
Reviewed-on: https://chromium-review.googlesource.com/1070453
Reviewed-by: agrieve <[email protected]>
Commit-Queue: Peter Wen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#561184}
diff --git a/docs/android_studio.md b/docs/android_studio.md
index b03a186..c97280c 100644
--- a/docs/android_studio.md
+++ b/docs/android_studio.md
@@ -22,8 +22,9 @@
 The above commands create a project dir `gradle` under your output directory.
 Use `--project-dir <project-dir>` to change this.
 
-See [android_test_instructions.md](android_test_instructions.md#Using-Emulators)
-for more information about building and running emulators.
+To import the project:
+* Use "Import Project", and select the directory containing the generated
+  project, e.g. `out/Debug/gradle`.
 
 For first-time Android Studio users:
 * Only run the setup wizard if you are planning to use emulators.
@@ -31,9 +32,8 @@
       for emulation.
     * To skip it, select "Cancel" when it comes up.
 
-To import the project:
-* Use "Import Project", and select the directory containing the generated
-  project, e.g. `out/Debug/gradle`.
+See [android_test_instructions.md](android_test_instructions.md#Using-Emulators)
+for more information about building and running emulators.
 
 If you're asked to use Studio's Android SDK:
 * No. (Always use your project's SDK configured by generate_gradle.py)