Fix IDL dependency computation for partial interfaces

Current IDL dependencies consider partial interfaces as dependencies
for *all* IDL files (to avoid having to resolve it to a particular file).

The code has 2 mistakes, however:
1. It fails to do this for supplemental IDL files (notably testing),
  which have just gotten a partial interface.
2. There's a typo in a regex, which means it fails on simple IDL files.

This fixes both bugs, and simplifies the partial interface determination code.

This fixes the problem that required this revert:
Revert r160289 "Vibration cannot be canceled during pattern vibration."
https://codereview.chromium.org/30063003/

This should allow this CL to be relanded:
Vibration cannot be canceled during pattern vibration.
https://codereview.chromium.org/18478003/

To verify that this CL works (excluding testing),
verify that NavigationVibration.idl is a global dependency:
cd "$CHROMIUM_DIR"
regyp  # eg gclient runhooks
ninja -C out/Release -j100 all_webkit
touch third_party/WebKit/Source/modules/vibration/NavigatorVibration.idl
ninja -C out/Release -j100 all_webkit  # should rebuild all bindings

To verify that it has fixed the problem,
apply the patch and verify InternalVibration.idl is a global dependency:
cd "$BLINK_DIR"
git co -b reland-vibe
git cl patch 18478003

cd "$CHROMIUM_DIR"
regyp  # eg gclient runhooks
ninja -C out/Release -j100 all_webkit
touch third_party/WebKit/Source/modules/vibration/testing/InternalsVibration.idl
ninja -C out/Release -j100 all_webkit  # should rebuild all bindings

BUG=222504, 261467, 310137

Review URL: https://codereview.chromium.org/29323008

git-svn-id: svn://svn.chromium.org/blink/trunk@160362 bbb929c8-8fbe-4397-9dbb-9b2b20218538