Bug 1442355 - Add a getter for docshell's colormatrix. r=smaug

--HG--
extra : rebase_source : ceb177980b2da2e0efa3e78a68f9bc299386355f

docshell/base/nsDocShell.cpp

@@ -14528,3 +14528,26 @@ nsDocShell::SetColorMatrix(float* aMatrix, uint32_t aMatrixLen)
 
   return NS_OK;
 }
+
+NS_IMETHODIMP
+nsDocShell::GetColorMatrix(uint32_t* aMatrixLen, float** aMatrix)
+{
+  NS_ENSURE_ARG_POINTER(aMatrixLen);
+  *aMatrixLen = 0;
+
+  NS_ENSURE_ARG_POINTER(aMatrix);
+  *aMatrix = nullptr;
+
+  if (mColorMatrix) {
+    *aMatrix = (float*)moz_xmalloc(20 * sizeof(float));
+    if (!*aMatrix) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    MOZ_ASSERT(20 * sizeof(float) == sizeof(mColorMatrix->components));
+    *aMatrixLen = 20;
+    memcpy(*aMatrix, mColorMatrix->components, 20 * sizeof(float));
+  }
+
+  return NS_OK;
+}

docshell/base/nsIDocShell.idl

@@ -1186,6 +1186,9 @@ interface nsIDocShell : nsIDocShellTreeItem
   void setColorMatrix([array, size_is(aMatrixLen)] in float aMatrix,
                       [optional] in unsigned long aMatrixLen);
 
+  void getColorMatrix([optional] out unsigned long aMatrixLen,
+                      [array, size_is(aMatrixLen), retval] out float aMatrix);
+
 %{C++
   /**
    * These methods call nsDocShell::GetHTMLEditorInternal() and