Allow SkLazyPixelRef to use SkScaledImageCache

-   SkScaledImageCache:
    -   Add new FindAndLock/AddAndLock variants that work well with
        SkLazyPixelRefs (take width, height, generation_id).
    -   Add static versions of these new variants.

-   SkLazyPixelRef:
    -   If NULL passed in as SkImageCache* in the constructor, it will
        now default to using the static SkScaledImageCache methods to
        cache decoded images.
    -   If (fImageCache==NULL), the default allocator can be changed
        with the setAllocator method.  If (fImageCache!=NULL), the
        SkImageCache handles allocation.

-   CachedDecodingPixelRefTest to test the new functionality.

BUG=
R=scroggo@google.com, mtklein@google.com, reed@google.com

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/37343002

git-svn-id: http://skia.googlecode.com/svn/trunk/gyp@12006 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests.gyp b/tests.gyp
index 2e04de1..6b286bb 100644
--- a/tests.gyp
+++ b/tests.gyp
@@ -10,6 +10,7 @@
       'include_dirs' : [
         '../src/core',
         '../src/effects',
+        '../src/image',
         '../src/lazy',
         '../src/pathops',
         '../src/pdf',
@@ -34,6 +35,7 @@
         '../tests/BitSetTest.cpp',
         '../tests/BlitRowTest.cpp',
         '../tests/BlurTest.cpp',
+        '../tests/CachedDecodingPixelRefTest.cpp',
         '../tests/CanvasTest.cpp',
         '../tests/CanvasStateTest.cpp',
         '../tests/ChecksumTest.cpp',