diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index 17f2a3144e4b..4e3199e188ce 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -520,7 +520,7 @@ ContentChild::RecvSetXPCOMProcessAttributes(const XPCOMInitData& aXPCOMInit,
 {
   mLookAndFeelCache = aLookAndFeelIntCache;
   InitXPCOM(aXPCOMInit, aInitialData);
-  InitGraphicsDeviceData();
+  InitGraphicsDeviceData(aXPCOMInit.contentDeviceData());
   return IPC_OK();
 }
 
@@ -952,11 +952,11 @@ ContentChild::AppendProcessId(nsACString& aName)
 }
 
 void
-ContentChild::InitGraphicsDeviceData()
+ContentChild::InitGraphicsDeviceData(const ContentDeviceData& aData)
 {
   // Initialize the graphics platform. This may contact the parent process
   // to read device preferences.
-  gfxPlatform::GetPlatform();
+  gfxPlatform::InitChild(aData);
 }
 
 void
diff --git a/dom/ipc/ContentChild.h b/dom/ipc/ContentChild.h
index 05253771d379..ef69b06d7670 100644
--- a/dom/ipc/ContentChild.h
+++ b/dom/ipc/ContentChild.h
@@ -104,7 +104,7 @@ public:
   void InitXPCOM(const XPCOMInitData& aXPCOMInit,
                  const mozilla::dom::ipc::StructuredCloneData& aInitialData);
 
-  void InitGraphicsDeviceData();
+  void InitGraphicsDeviceData(const ContentDeviceData& aData);
 
   static ContentChild* GetSingleton()
   {
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index ec7b97df72bd..4d35e0970ace 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -2222,6 +2222,8 @@ ContentParent::InitInternal(ProcessPriority aInitialPriority,
     SerializeURI(nullptr, xpcomInit.userContentSheetURL());
   }
 
+  gfxPlatform::GetPlatform()->BuildContentDeviceData(&xpcomInit.contentDeviceData());
+
   nsCOMPtr<nsIGfxInfo> gfxInfo = services::GetGfxInfo();
   if (gfxInfo) {
     for (int32_t i = 1; i <= nsIGfxInfo::FEATURE_MAX_VALUE; ++i) {
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 26b6f9cf533e..12d82becfdc2 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -265,6 +265,7 @@ struct XPCOMInitData
     FontFamilyListEntry[] fontFamilies;
     OptionalURIParams userContentSheetURL;
     PrefSetting[] prefs;
+    ContentDeviceData contentDeviceData;
     GfxInfoFeatureStatus[] gfxFeatureStatus;
     DataStorageEntry[] dataStorage;
 };
diff --git a/gfx/ipc/D3DMessageUtils.cpp b/gfx/ipc/D3DMessageUtils.cpp
index f3895fdae95c..30a2b88734b3 100644
--- a/gfx/ipc/D3DMessageUtils.cpp
+++ b/gfx/ipc/D3DMessageUtils.cpp
@@ -47,8 +47,6 @@ ParamTraits<DxgiAdapterDesc>::Write(Message* aMsg, const paramType& aParam)
   WriteParam(aMsg, aParam.SharedSystemMemory);
   WriteParam(aMsg, aParam.AdapterLuid.LowPart);
   WriteParam(aMsg, aParam.AdapterLuid.HighPart);
-#else
-  MOZ_ASSERT_UNREACHABLE("DxgiAdapterDesc is Windows-only");
 #endif
 }
 
@@ -72,10 +70,10 @@ ParamTraits<DxgiAdapterDesc>::Read(const Message* aMsg, PickleIterator* aIter, p
   {
     return true;
   }
-#else
-  MOZ_ASSERT_UNREACHABLE("DxgiAdapterDesc is Windows-only");
-#endif
   return false;
+#else
+  return true;
+#endif
 }
 
 } // namespace IPC
diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index 82167c1b264e..e754ab6c24f6 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -152,6 +152,8 @@ using namespace mozilla::gfx;
 gfxPlatform *gPlatform = nullptr;
 static bool gEverInitialized = false;
 
+const ContentDeviceData* gContentDeviceInitData = nullptr;
+
 static Mutex* gGfxPlatformPrefsLock = nullptr;
 
 // These two may point to the same profile
@@ -528,6 +530,8 @@ gfxPlatform*
 gfxPlatform::GetPlatform()
 {
     if (!gPlatform) {
+        MOZ_RELEASE_ASSERT(!XRE_IsContentProcess(),
+                           "Content Process should have called InitChild() before first GetPlatform()");
         Init();
     }
     return gPlatform;
@@ -539,6 +543,19 @@ gfxPlatform::Initialized()
   return !!gPlatform;
 }
 
+/* static */ void
+gfxPlatform::InitChild(const ContentDeviceData& aData)
+{
+  MOZ_ASSERT(XRE_IsContentProcess());
+  MOZ_RELEASE_ASSERT(!gPlatform,
+                     "InitChild() should be called before first GetPlatform()");
+  // Make the provided initial ContentDeviceData available to the init
+  // routines, so they don't have to do a sync request from the parent.
+  gContentDeviceInitData = &aData;
+  Init();
+  gContentDeviceInitData = nullptr;
+}
+
 void RecordingPrefChanged(const char *aPrefName, void *aClosure)
 {
   if (Preferences::GetBool("gfx.2d.recording", false)) {
@@ -2651,6 +2668,11 @@ gfxPlatform::FetchAndImportContentDeviceData()
 {
   MOZ_ASSERT(XRE_IsContentProcess());
 
+  if (gContentDeviceInitData) {
+    ImportContentDeviceData(*gContentDeviceInitData);
+    return;
+  }
+
   mozilla::dom::ContentChild* cc = mozilla::dom::ContentChild::GetSingleton();
 
   mozilla::gfx::ContentDeviceData data;
diff --git a/gfx/thebes/gfxPlatform.h b/gfx/thebes/gfxPlatform.h
index 698d248dc708..ee6b299d75b7 100644
--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@@ -175,6 +175,12 @@ public:
      */
     static void Shutdown();
 
+    /**
+     * Initialize gfxPlatform (if not already done) in a child process, with
+     * the provided ContentDeviceData.
+     */
+    static void InitChild(const mozilla::gfx::ContentDeviceData& aData);
+
     static void InitLayersIPC();
     static void ShutdownLayersIPC();