Bug 1269936 - Introduce and call a runtime-wide servo initialization hook. r=heycam

layout/build/nsLayoutStatics.cpp

@@ -129,6 +129,7 @@ using namespace mozilla::system;
 #include "MediaDecoder.h"
 #include "mozilla/layers/CompositorLRU.h"
 #include "mozilla/dom/devicestorage/DeviceStorageStatics.h"
+#include "mozilla/ServoBindings.h"
 #include "mozilla/StaticPresData.h"
 
 #ifdef MOZ_B2G_BT
@@ -317,6 +318,10 @@ nsLayoutStatics::Initialize()
 
   mozilla::dom::WebCryptoThreadPool::Initialize();
 
+#ifdef MOZ_STYLO
+  Servo_Initialize();
+#endif
+
   return NS_OK;
 }
 

layout/style/ServoBindings.cpp

@@ -296,6 +296,13 @@ Servo_ReleaseComputedValues(ServoComputedValues*)
             "non-MOZ_STYLO build");
 }
 
+void
+Servo_Initialize()
+{
+  MOZ_CRASH("stylo: shouldn't be calling Servo_Initialize in a "
+            "non-MOZ_STYLO build");
+}
+
 void
 Servo_RestyleDocument(RawGeckoDocument* doc, RawServoStyleSet* set)
 {

layout/style/ServoBindings.h

@@ -93,7 +93,10 @@ ServoComputedValues* Servo_GetComputedValuesForPseudoElement(ServoComputedValues
 void Servo_AddRefComputedValues(ServoComputedValues*);
 void Servo_ReleaseComputedValues(ServoComputedValues*);
 
-// Servo API.
+// Initialize Servo components. Should be called exactly once at startup.
+void Servo_Initialize();
+
+// Restyle the given document.
 void Servo_RestyleDocument(RawGeckoDocument* doc, RawServoStyleSet* set);
 
 // Style-struct management.