Make MediaScanner extract "date taken" from videos, if present

Bug: 29530912
Change-Id: Ibb85243c3d225faff5f17ec545e395a2e00acd0a
diff --git a/media/libstagefright/StagefrightMediaScanner.cpp b/media/libstagefright/StagefrightMediaScanner.cpp
index db33e83..8935f6a 100644
--- a/media/libstagefright/StagefrightMediaScanner.cpp
+++ b/media/libstagefright/StagefrightMediaScanner.cpp
@@ -122,6 +122,7 @@
         { "writer", METADATA_KEY_WRITER },
         { "compilation", METADATA_KEY_COMPILATION },
         { "isdrm", METADATA_KEY_IS_DRM },
+        { "date", METADATA_KEY_DATE },
         { "width", METADATA_KEY_VIDEO_WIDTH },
         { "height", METADATA_KEY_VIDEO_HEIGHT },
     };