Bug 1286168 - Add a RAII class to initialize ImageLib services in GTests. r=njn

image/test/gtest/Common.h

@@ -15,6 +15,7 @@
 #include "mozilla/gfx/2D.h"
 #include "Decoder.h"
 #include "gfxColor.h"
+#include "imgITools.h"
 #include "nsCOMPtr.h"
 #include "SurfacePipe.h"
 #include "SurfacePipeFactory.h"
@@ -99,6 +100,23 @@ struct BGRAColor
 // General Helpers
 ///////////////////////////////////////////////////////////////////////////////
 
+/**
+ * A RAII class that ensure that ImageLib services are available. Any tests that
+ * require ImageLib to be initialized (for example, any test that uses the
+ * SurfaceCache; see image::EnsureModuleInitialized() for the full list) can
+ * use this class to ensure that ImageLib services are available. Failure to do
+ * so can result in strange, non-deterministic failures.
+ */
+struct AutoInitializeImageLib
+{
+  AutoInitializeImageLib()
+  {
+    // Ensure that ImageLib services are initialized.
+    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
+    EXPECT_TRUE(imgTools != nullptr);
+  }
+};
+
 /// Loads a file from the current directory. @return an nsIInputStream for it.
 already_AddRefed<nsIInputStream> LoadFile(const char* aRelativePath);
 

image/test/gtest/TestDecodeToSurface.cpp

@@ -87,13 +87,8 @@ RunDecodeToSurface(const ImageTestCase& aTestCase)
 
 class ImageDecodeToSurface : public ::testing::Test
 {
-  protected:
-  static void SetUpTestCase()
-  {
-    // Ensure that ImageLib services are initialized.
-    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
-    EXPECT_TRUE(imgTools != nullptr);
-  }
+protected:
+  AutoInitializeImageLib mInit;
 };
 
 TEST_F(ImageDecodeToSurface, PNG) { RunDecodeToSurface(GreenPNGTestCase()); }

image/test/gtest/TestDecoders.cpp

@@ -206,13 +206,8 @@ CheckDownscaleDuringDecode(const ImageTestCase& aTestCase)
 
 class ImageDecoders : public ::testing::Test
 {
-  protected:
-  static void SetUpTestCase()
-  {
-    // Ensure that ImageLib services are initialized.
-    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
-    EXPECT_TRUE(imgTools != nullptr);
-  }
+protected:
+  AutoInitializeImageLib mInit;
 };
 
 TEST_F(ImageDecoders, PNGSingleChunk)

image/test/gtest/TestDeinterlacingFilter.cpp

@@ -61,13 +61,8 @@ AssertConfiguringDeinterlacingFilterFails(const IntSize& aSize)
 
 class ImageDeinterlacingFilter : public ::testing::Test
 {
-  protected:
-  static void SetUpTestCase()
-  {
-    // Ensure that ImageLib services are initialized.
-    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
-    EXPECT_TRUE(imgTools != nullptr);
-  }
+protected:
+  AutoInitializeImageLib mInit;
 };
 
 TEST_F(ImageDeinterlacingFilter, WritePixels100_100)

image/test/gtest/TestMetadata.cpp

@@ -135,13 +135,8 @@ CheckMetadata(const ImageTestCase& aTestCase,
 
 class ImageDecoderMetadata : public ::testing::Test
 {
-  protected:
-  static void SetUpTestCase()
-  {
-    // Ensure that ImageLib services are initialized.
-    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
-    EXPECT_TRUE(imgTools != nullptr);
-  }
+protected:
+  AutoInitializeImageLib mInit;
 };
 
 TEST_F(ImageDecoderMetadata, PNG) { CheckMetadata(GreenPNGTestCase()); }

image/test/gtest/TestSurfacePipeIntegration.cpp

@@ -131,13 +131,8 @@ CheckPalettedSurfacePipeMethodResults(SurfacePipe* aPipe,
 
 class ImageSurfacePipeIntegration : public ::testing::Test
 {
-  protected:
-  static void SetUpTestCase()
-  {
-    // Ensure that ImageLib services are initialized.
-    nsCOMPtr<imgITools> imgTools = do_CreateInstance("@mozilla.org/image/tools;1");
-    EXPECT_TRUE(imgTools != nullptr);
-  }
+protected:
+  AutoInitializeImageLib mInit;
 };
 
 TEST_F(ImageSurfacePipeIntegration, SurfacePipe)