Re-land "Remove <(webrtc_root) from source file entries."

Changes differing from https://webrtc-codereview.appspot.com/37859004:
* I put the include_tests==1 stuff of audio_coding.gypi in its
  own audio_coding_tests.gypi file, including the Android and isolate
  targets which were incorrectly located in the previous CL
* I moved the bwe utilities in remote_bitrate_estimator.gypi
  into include_tests==1 since they depend on test.gyp after I
  cleaned up the duplicated inclusion of rtp_file_reader.cc

R=stefan@webrtc.org
TBR=tina.legrand@webrtc.org
TESTED=Passing gyp and compile using:
webrtc/build/gyp_webrtc -Dinclude_tests=1
webrtc/build/gyp_webrtc -Dinclude_tests=0
I also setup a Chromium checkout with my checkout mounted in
third_party/webrtc and ran build/gyp_chromium successfully.

BUG=4185

Review URL: https://webrtc-codereview.appspot.com/33159004

Cr-Commit-Position: refs/heads/master@{#8205}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8205 4adac7df-926f-26a2-2b94-8c16560cd09d

PRESUBMIT.py

@@ -127,7 +127,7 @@ def _CheckNoSourcesAboveGyp(input_api, gyp_files, output_api):
   # Disallow referencing source files with paths above the GYP file location.
   source_pattern = input_api.re.compile(r'sources.*?\[(.*?)\]',
                                         re.MULTILINE | re.DOTALL)
-  file_pattern = input_api.re.compile(r"'(\.\./.*?)'")
+  file_pattern = input_api.re.compile(r"'((\.\./.*?)|(<\(webrtc_root\).*?))'")
   violating_gyp_files = set()
   violating_source_entries = []
   for gyp_file in gyp_files: