Bug 595055 - Use the correct context when deleting textures, so we don't accidentally unset some state like the viewport. r=vlad a=b

gfx/thebes/GLContext.cpp

@@ -44,6 +44,8 @@
 
 #include "prlink.h"
 
+#include "nsThreadUtils.h"
+
 #include "gfxImageSurface.h"
 #include "GLContext.h"
 #include "GLContextProvider.h"
@@ -436,12 +438,19 @@ GLContext::CreateTextureImage(const nsIntSize& aSize,
 
 BasicTextureImage::~BasicTextureImage()
 {
-    nsRefPtr<GLContext> ctx = mGLContext->GetSharedContext();
+    GLContext *ctx = mGLContext;
-    if (!ctx) {
+    if (ctx->IsDestroyed() || !NS_IsMainThread()) {
-      ctx = mGLContext;
+        ctx = ctx->GetSharedContext();
+    }
+
+    // If we have a context, then we need to delete the texture;
+    // if we don't have a context (either real or shared),
+    // then they went away when the contex was deleted, because it
+    // was the only one that had access to it.
+    if (ctx && !ctx->IsDestroyed()) {
+        mGLContext->MakeCurrent();
+        mGLContext->fDeleteTextures(1, &mTexture);
     }
-    ctx->MakeCurrent();
-    ctx->fDeleteTextures(1, &mTexture);
 }
 
 gfxContext*

gfx/thebes/GLContext.h

@@ -393,6 +393,11 @@ public:
     // the GL function pointers!
     void THEBES_API MarkDestroyed();
 
+    PRBool IsDestroyed() {
+        // MarkDestroyed will mark all these as null.
+        return fUseProgram == nsnull;
+    }
+
     enum NativeDataType {
       NativeGLContext,
       NativeImageSurface,