Bug 1276132 - Make more Widevine class constructors explicit to keep gcc happy. r=jwwang

Fixes compile errors on Linux when Widevine is compiled.

MozReview-Commit-ID: 19qQw02CqdQ

--HG--
extra : rebase_source : ebb98b25738e0438d873834f07c72be1f4eb71db

dom/media/gmp/widevine-adapter/WidevineDecryptor.cpp

@@ -193,7 +193,7 @@ WidevineDecryptor::DecryptingComplete()
 
 class WidevineBuffer : public cdm::Buffer {
 public:
-  WidevineBuffer(size_t aSize) {
+  explicit WidevineBuffer(size_t aSize) {
     Log("WidevineBuffer(size=" PRIuSIZE ") created", aSize);
     mBuffer.SetLength(aSize);
   }

dom/media/gmp/widevine-adapter/WidevineUtils.h

@@ -46,7 +46,7 @@ class CDMWrapper {
 public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CDMWrapper)
 
-  CDMWrapper(cdm::ContentDecryptionModule_8* aCDM)
+  explicit CDMWrapper(cdm::ContentDecryptionModule_8* aCDM)
     : mCDM(aCDM)
   {
     MOZ_ASSERT(mCDM);