Switch uses of SkChecksum::Compute to Murmur3.

SkChecksum::Compute is a very, very poorly distributed hash function.
This replaces all remaining uses with Murmur3.

The only interesting stuff is in src/gpu.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/1d024a3c909ae5cefa5e8b339e2b52dc73ee85ac

Committed: https://skia.googlesource.com/skia/+/540e95483d285b555e9b1a73d18c16e7d7c0deba

Review URL: https://codereview.chromium.org/1436973003
diff --git a/src/gpu/GrResourceCache.cpp b/src/gpu/GrResourceCache.cpp
index cb6bcf7..4a0c9b2 100644
--- a/src/gpu/GrResourceCache.cpp
+++ b/src/gpu/GrResourceCache.cpp
@@ -42,7 +42,7 @@
 }
 
 uint32_t GrResourceKeyHash(const uint32_t* data, size_t size) {
-    return SkChecksum::Compute(data, size);
+    return SkChecksum::Murmur3(data, size);
 }
 
 //////////////////////////////////////////////////////////////////////////////
@@ -564,7 +564,7 @@
             int currP = 0;
             int currNP = 0;
             while (currP < sortedPurgeableResources.count() &&
-                   currNP < fNonpurgeableResources.count()) {                
+                   currNP < fNonpurgeableResources.count()) {
                 uint32_t tsP = sortedPurgeableResources[currP]->cacheAccess().timestamp();
                 uint32_t tsNP = fNonpurgeableResources[currNP]->cacheAccess().timestamp();
                 SkASSERT(tsP != tsNP);
@@ -596,10 +596,10 @@
 
             // count should be the next timestamp we return.
             SkASSERT(fTimestamp == SkToU32(count));
-            
+
             // The historical timestamps of flushes are now invalid.
             this->resetFlushTimestamps();
-        }        
+        }
     }
     return fTimestamp++;
 }