Use SkMutex::assertHeld in SkPDFFont and SkPDFShader.

src/pdf/SkPDFShader.cpp

Index: src/pdf/SkPDFShader.cpp
diff --git a/src/pdf/SkPDFShader.cpp b/src/pdf/SkPDFShader.cpp
index 62adf5811db5a3672f73f5e1a8796b6c2596b779..c4d362baa573077430126b38cd11cc5f58bfa2cb 100644
--- a/src/pdf/SkPDFShader.cpp
+++ b/src/pdf/SkPDFShader.cpp
@@ -602,6 +602,7 @@ SkPDFObject* SkPDFShader::GetPDFShaderByState(State* inState) {
         return NULL;
     }
 
+    SkPDFShader::CanonicalShadersMutex().assertHeld();

[mtklein, 2014/06/20 17:40:54]

Seems redundant?  Just let CanonicalShaders() do it?

[hal.canary, 2014/06/20 17:49:07]

Done.

     ShaderCanonicalEntry entry(NULL, shaderState.get());
     int index = CanonicalShaders().find(entry);
     if (index >= 0) {
@@ -635,6 +636,7 @@ SkPDFObject* SkPDFShader::GetPDFShaderByState(State* inState) {
         return NULL;
     }
     entry.fPDFShader = result;
+    SkPDFShader::CanonicalShadersMutex().assertHeld();

[mtklein, 2014/06/20 17:40:56]

Ditto.

[hal.canary, 2014/06/20 17:49:06]

Done.

     CanonicalShaders().push(entry);
     return result;  // return the reference that came from new.
 }
@@ -659,6 +661,7 @@ SkPDFObject* SkPDFShader::GetPDFShader(const SkShader& shader,
 
 // static
 SkTDArray<SkPDFShader::ShaderCanonicalEntry>& SkPDFShader::CanonicalShaders() {
+    SkPDFShader::CanonicalShadersMutex().assertHeld();
     // This initialization is only thread safe with gcc.
     static SkTDArray<ShaderCanonicalEntry> gCanonicalShaders;
     return gCanonicalShaders;
@@ -674,7 +677,7 @@ SkBaseMutex& SkPDFShader::CanonicalShadersMutex() {
 
 // static
 SkPDFObject* SkPDFFunctionShader::RangeObject() {
-    // This initialization is only thread safe with gcc.
+    SkPDFShader::CanonicalShadersMutex().assertHeld();
     static SkPDFArray* range = NULL;
     // This method is only used with CanonicalShadersMutex, so it's safe to
     // populate domain.