[Fuchsia] Don't use protected memory on x64.

Protected memory and HW decoders are not supported on x64 devices,
so WebEngine wasn't working properly when WIDEVINE_CDM feature was
enabled. This CL adds IsFuchsiaCdmSupported() that indicates that
that FuchsiaCdm is supported on the device. For now it's just a stub
that returns true only in arm64 builds.

With this change WebEngine will not try to use protected memory on
x64 devices where it's not supported.

Bug: 1013412
Change-Id: Ib9c323c725886ea7397bc7f2633a44fad56ee13a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1854547
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Auto-Submit: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705189}

fuchsia/engine/context_provider_impl.cc

@@ -33,6 +33,7 @@
 #include "base/strings/strcat.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
+#include "build/build_config.h"
 #include "components/viz/common/features.h"
 #include "content/public/common/content_switches.h"
 #include "fuchsia/engine/common/web_engine_content_client.h"
@@ -103,6 +104,20 @@ bool SetContentDirectoriesInCommandLine(
   return true;
 }
 
+// Returns true if DRM is supported in current configuration. Currently we
+// assume that it is supported on ARM64, but not on x64.
+//
+// TODO(crbug.com/1013412): Detect support for all features required for
+// FuchsiaCdm. Specifically we need to verify that protected memory is supported
+// and that mediacodec API provides hardware video decoders.
+bool IsFuchsiaCdmSupported() {
+#if defined(ARCH_CPU_ARM64)
+  return true;
+#else
+  return false;
+#endif
+}
+
 }  // namespace
 
 const uint32_t ContextProviderImpl::kContextRequestHandleId =
@@ -212,7 +227,17 @@ void ContextProviderImpl::Create(
   bool enable_widevine =
       (features & fuchsia::web::ContextFeatureFlags::WIDEVINE_CDM) ==
       fuchsia::web::ContextFeatureFlags::WIDEVINE_CDM;
+  if (enable_widevine && !IsFuchsiaCdmSupported()) {
+    LOG(WARNING) << "Widevine is not supported on this device.";
+    enable_widevine = false;
+  }
+
   bool enable_playready = params.has_playready_key_system();
+  if (enable_playready && !IsFuchsiaCdmSupported()) {
+    LOG(WARNING) << "PlayReady is not supported on this device.";
+    enable_playready = false;
+  }
+
   bool enable_protected_graphics = enable_widevine || enable_playready;
 
   if (enable_protected_graphics && !enable_vulkan) {

fuchsia/engine/renderer/web_engine_content_renderer_client.cc

@@ -22,8 +22,8 @@ namespace {
 
 // Returns true if the specified video format can be decoded on hardware.
 bool IsSupportedHardwareVideoCodec(const media::VideoType& type) {
-  // TODO(fxb/36000): Replace these hardcoded checks with a query to the
-  // fuchsia.mediacodec FIDL service.
+  // TODO(crbug.com/1013412): Replace these hardcoded checks with a query to the
+  // fuchsia.mediacodec FIDL service when fxb/36000 is resolved.
   if (type.codec == media::kCodecH264 && type.level <= 41)
     return true;