Include a new heap summary line in the SIGQUIT output.

Looks like this:

  Heap: 87% free, 4MB/32MB; 6327 objects

While I'm here, fix another long-standing TODO to make PrettySize have the
usual google3 behavior. (I took the specific thresholds from Chromium.)

Also distinguish between the more general "Dump" member functions and the
specific SIGQUIT-related ones by consistently calling the latter DumpForSigQuit.

Change-Id: I76e783adc18dd089bac9b348f53dc9860a0fe4b9
diff --git a/src/utils_test.cc b/src/utils_test.cc
index e0b2139..311bd16 100644
--- a/src/utils_test.cc
+++ b/src/utils_test.cc
@@ -135,15 +135,17 @@
   if (sizeof(size_t) > sizeof(uint32_t)) {
     EXPECT_EQ("100GB", PrettySize(100 * GB));
   }
-  EXPECT_EQ("1MB", PrettySize(1 * MB));
+  EXPECT_EQ("1024KB", PrettySize(1 * MB));
   EXPECT_EQ("10MB", PrettySize(10 * MB));
   EXPECT_EQ("100MB", PrettySize(100 * MB));
-  EXPECT_EQ("1KB", PrettySize(1 * KB));
+  EXPECT_EQ("1024B", PrettySize(1 * KB));
   EXPECT_EQ("10KB", PrettySize(10 * KB));
   EXPECT_EQ("100KB", PrettySize(100 * KB));
+  EXPECT_EQ("0B", PrettySize(0));
   EXPECT_EQ("1B", PrettySize(1));
   EXPECT_EQ("10B", PrettySize(10));
   EXPECT_EQ("100B", PrettySize(100));
+  EXPECT_EQ("512B", PrettySize(512));
 }
 
 TEST_F(UtilsTest, PrettyDuration) {