SkSharedMutex::acquire to check thread state.

This makes SkSharedMutex::acquire() assert if a thread has already
acquired a shared lock.

Change-Id: I35a186a137b9efcad1132093e1bb18c8822e1538
Reviewed-on: https://skia-review.googlesource.com/128160
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/core/SkSharedMutex.cpp b/src/core/SkSharedMutex.cpp
index 17714a7185..d3e7663bca 100644
--- a/src/core/SkSharedMutex.cpp
+++ b/src/core/SkSharedMutex.cpp
@@ -132,6 +132,9 @@
         {
             SkAutoMutexAcquire l(&fMu);
 
+            SkASSERTF(!fCurrentShared->find(threadID),
+                      "Thread %lx already has an shared lock\n", threadID);
+
             if (!fWaitingExclusive->tryAdd(threadID)) {
                 SkDEBUGFAILF("Thread %lx already has an exclusive lock\n", threadID);
             }