support scaledimagecache instantiable using discardablememory

tests/ImageCacheTest.cpp

Index: tests/ImageCacheTest.cpp
diff --git a/tests/ImageCacheTest.cpp b/tests/ImageCacheTest.cpp
index b8815a32170da030c332ff12ef16889bfc2ee2bb..69de629579f857ca2799892b9b37db9794912e32 100644
--- a/tests/ImageCacheTest.cpp
+++ b/tests/ImageCacheTest.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "Test.h"
+#include "SkDiscardableMemory.h"
 #include "SkScaledImageCache.h"
 
 static void make_bm(SkBitmap* bm, int w, int h) {
@@ -13,27 +14,27 @@ static void make_bm(SkBitmap* bm, int w, int h) {
     bm->allocPixels();
 }
 
-static void TestImageCache(skiatest::Reporter* reporter) {
-    static const int COUNT = 10;
-    static const int DIM = 256;
-    static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
-    SkScaledImageCache cache(defLimit);
-    SkScaledImageCache::ID* id;
+static const int COUNT = 10;
+static const int DIM = 256;
 
+static void test_cache(skiatest::Reporter* reporter, SkScaledImageCache& cache,
+                       bool testPurge) {
+    SkScaledImageCache::ID* id;
+    
     SkBitmap bm[COUNT];
-
+    
     SkScalar scale = 2;
     for (int i = 0; i < COUNT; ++i) {
         SkBitmap tmp;
-
+        
         make_bm(&bm[i], DIM, DIM);
         id = cache.findAndLock(bm[i], scale, scale, &tmp);
         REPORTER_ASSERT(reporter, NULL == id);
-
+        
         make_bm(&tmp, DIM, DIM);
         id = cache.addAndLock(bm[i], scale, scale, tmp);
         REPORTER_ASSERT(reporter, NULL != id);
-
+        
         SkBitmap tmp2;
         SkScaledImageCache::ID* id2 = cache.findAndLock(bm[i], scale, scale,
                                                         &tmp2);
@@ -42,25 +43,38 @@ static void TestImageCache(skiatest::Reporter* reporter) {
         REPORTER_ASSERT(reporter, tmp.width() == tmp2.width());
         REPORTER_ASSERT(reporter, tmp.height() == tmp2.height());
         cache.unlock(id2);
-
+        
         cache.unlock(id);
     }
-
-    // stress test, should trigger purges
-    for (size_t i = 0; i < COUNT * 100; ++i) {
-        scale += 1;
-
-        SkBitmap tmp;
-
-        make_bm(&tmp, DIM, DIM);
-        id = cache.addAndLock(bm[0], scale, scale, tmp);
-        REPORTER_ASSERT(reporter, NULL != id);
-        cache.unlock(id);
+    
+    if (testPurge) {
+        // stress test, should trigger purges
+        for (size_t i = 0; i < COUNT * 100; ++i) {
+            scale += 1;
+            
+            SkBitmap tmp;
+            
+            make_bm(&tmp, DIM, DIM);
+            id = cache.addAndLock(bm[0], scale, scale, tmp);
+            REPORTER_ASSERT(reporter, NULL != id);
+            cache.unlock(id);
+        }
     }
-
     cache.setByteLimit(0);
 }
 
+static void TestImageCache(skiatest::Reporter* reporter) {
+    {
+        static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
+        SkScaledImageCache cache(defLimit);
+        test_cache(reporter, cache, true);
+    }
+    {
+        SkScaledImageCache cache(SkDiscardableMemory::Create);
+        test_cache(reporter, cache, false);
+    }
+}
+
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("ImageCache", TestImageCacheClass, TestImageCache)