Re-land fix for Media Foundation crash. Remove Vista support.

Original description:

Do a thorough check for the availability of the Media Foundation DLLs.
Comments from code:
On Vista this API is an optional download but the API is
advertised as a part of Windows 7 and onwards. However,
we've seen that the required DLLs are not available in some
Win7 distributions such as Windows 7 N and Windows 7 KN.

BUG=164654
TEST=Run media_unittests. See more details in the bug report.

TBR=mflodman


Review URL: https://chromiumcodereview.appspot.com/11500009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@172132 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 38 insertions, 10 deletions

diff --git a/media/video/capture/win/video_capture_device_mf_win.cc b/media/video/capture/win/video_capture_device_mf_win.cc
index 131bc7e..96bfdb2 100644
--- a/media/video/capture/win/video_capture_device_mf_win.cc
+++ b/media/video/capture/win/video_capture_device_mf_win.cc
@@ -12,6 +12,7 @@
 #include "base/synchronization/waitable_event.h"
 #include "base/sys_string_conversions.h"
 #include "base/win/scoped_co_mem.h"
+#include "base/win/windows_version.h"
 #include "media/video/capture/win/capability_list_win.h"
 
 using base::win::ScopedCoMem;
@@ -143,6 +144,23 @@ HRESULT FillCapabilities(IMFSourceReader* source,
   return (hr == MF_E_NO_MORE_TYPES) ? S_OK : hr;
 }
 
+bool LoadMediaFoundationDlls() {
+  static const wchar_t* const kMfDLLs[] = {
+    L"%WINDIR%\\system32\\mf.dll",
+    L"%WINDIR%\\system32\\mfplat.dll",
+    L"%WINDIR%\\system32\\mfreadwrite.dll",
+  };
+
+  for (int i = 0; i < arraysize(kMfDLLs); ++i) {
+    wchar_t path[MAX_PATH] = {0};
+    ExpandEnvironmentStringsW(kMfDLLs[i], path, arraysize(path));
+    if (!LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH))
+      return false;
+  }
+
+  return true;
+}
+
 }  // namespace
 
 class MFReaderCallback
@@ -222,6 +240,17 @@ class MFReaderCallback
 };
 
 // static
+bool VideoCaptureDeviceMFWin::PlatformSupported() {
+  // Even though the DLLs might be available on Vista, we get crashes
+  // when running our tests on the build bots.
+  if (base::win::GetVersion() < base::win::VERSION_WIN7)
+    return false;
+
+  static bool g_dlls_available = LoadMediaFoundationDlls();
+  return g_dlls_available;
+}
+
+// static
 void VideoCaptureDeviceMFWin::GetDeviceNames(Names* device_names) {
   ScopedCoMem<IMFActivate*> devices;
   UINT32 count;
diff --git a/media/video/capture/win/video_capture_device_mf_win.h b/media/video/capture/win/video_capture_device_mf_win.h
index 6f229b05..773b1ed 100644
--- a/media/video/capture/win/video_capture_device_mf_win.h
+++ b/media/video/capture/win/video_capture_device_mf_win.h
@@ -46,6 +46,13 @@ class VideoCaptureDeviceMFWin
   virtual void DeAllocate() OVERRIDE;
   virtual const Name& device_name() OVERRIDE;
 
+  // Returns true iff the current platform supports the Media Foundation API
+  // and that the DLLs are available.  On Vista this API is an optional download
+  // but the API is advertised as a part of Windows 7 and onwards.  However,
+  // we've seen that the required DLLs are not available in some Win7
+  // distributions such as Windows 7 N and Windows 7 KN.
+  static bool PlatformSupported();
+
   static void GetDeviceNames(Names* device_names);
 
   // Captured a new video frame.
diff --git a/media/video/capture/win/video_capture_device_win.cc b/media/video/capture/win/video_capture_device_win.cc
index e83b15e6d..875ca00 100644
--- a/media/video/capture/win/video_capture_device_win.cc
+++ b/media/video/capture/win/video_capture_device_win.cc
@@ -10,7 +10,6 @@
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
 #include "base/win/scoped_variant.h"
-#include "base/win/windows_version.h"
 #include "media/video/capture/win/video_capture_device_mf_win.h"
 
 using base::win::ScopedComPtr;
@@ -144,20 +143,13 @@ void DeleteMediaType(AM_MEDIA_TYPE* mt) {
   }
 }
 
-bool ShouldUseMediaFoundationAPI() {
-  // Although Media Foundation is supported on Vista, it requires a special
-  // update to be available.  For now we don't risk it and use DirectShow
-  // on Vista but MF on Win7 and higher.
-  return base::win::GetVersion() >= base::win::VERSION_WIN7;
-}
-
 }  // namespace
 
 namespace media {
 
 // static
 void VideoCaptureDevice::GetDeviceNames(Names* device_names) {
-  if (ShouldUseMediaFoundationAPI()) {
+  if (VideoCaptureDeviceMFWin::PlatformSupported()) {
     VideoCaptureDeviceMFWin::GetDeviceNames(device_names);
   } else {
     VideoCaptureDeviceWin::GetDeviceNames(device_names);
@@ -167,7 +159,7 @@ void VideoCaptureDevice::GetDeviceNames(Names* device_names) {
 // static
 VideoCaptureDevice* VideoCaptureDevice::Create(const Name& device_name) {
   VideoCaptureDevice* ret = NULL;
-  if (ShouldUseMediaFoundationAPI()) {
+  if (VideoCaptureDeviceMFWin::PlatformSupported()) {
     scoped_ptr<VideoCaptureDeviceMFWin> device(
         new VideoCaptureDeviceMFWin(device_name));
     if (device->Init())