Add two creation flags to OMXCodec::Create()

o This allows to force to use software codecs or hardware codecs
o If request cannot be fullfilled, Create() returns NULL.

Change-Id: I02b56a9229abb56d49703fe80ac18571d33f3748

include/media/stagefright/OMXCodec.h

@@ -39,6 +39,11 @@ struct OMXCodec : public MediaSource,
         // The client wants to access the output buffer's video
         // data for example for thumbnail extraction.
         kClientNeedsFramebuffer  = 4,
+
+        // Request for software or hardware codecs. If request
+        // can not be fullfilled, Create() returns NULL.
+        kSoftwareCodecsOnly      = 8,
+        kHardwareCodecsOnly      = 16,
     };
     static sp<MediaSource> Create(
             const sp<IOMX> &omx,

media/libstagefright/OMXCodec.cpp

@@ -450,7 +450,16 @@ void OMXCodec::findMatchingCodecs(
             continue;
         }
 
-        matchingCodecs->push(String8(componentName));
+        // When requesting software-only codecs, only push software codecs
+        // When requesting hardware-only codecs, only push hardware codecs
+        // When there is request neither for software-only nor for
+        // hardware-only codecs, push all codecs
+        if (((flags & kSoftwareCodecsOnly) &&   IsSoftwareCodec(componentName)) ||
+            ((flags & kHardwareCodecsOnly) &&  !IsSoftwareCodec(componentName)) ||
+            (!(flags & (kSoftwareCodecsOnly | kHardwareCodecsOnly)))) {
+
+            matchingCodecs->push(String8(componentName));
+        }
     }
 
     if (flags & kPreferSoftwareCodecs) {