supersize: Add "diff" command

tools/binary_size/libsupersize/testdata/ActualDiff.golden

Index: tools/binary_size/libsupersize/testdata/ActualDiff.golden
diff --git a/tools/binary_size/libsupersize/testdata/ActualDiff.golden b/tools/binary_size/libsupersize/testdata/ActualDiff.golden
index 2299ddb196b1b1cedc930a176fec56cc26f3fd6c..13dc1947119947ab77c85f7665c76699f7bcba5b 100644
--- a/tools/binary_size/libsupersize/testdata/ActualDiff.golden
+++ b/tools/binary_size/libsupersize/testdata/ActualDiff.golden
@@ -2,9 +2,9 @@ Common Metadata:
     baz=yes
     foo=1
 Old Metadata:
-    bar=[1, 3]
-New Metadata:
     bar=[1, 2, 3]
+New Metadata:
+    bar=[1, 3]
 
 Section Sizes (Total=0 bytes):
     .bss: 0 bytes (not included in totals)
@@ -49,135 +49,135 @@ Other section sizes:
     .strtab: 0 bytes
     .symtab: 0 bytes
 
-3 symbols added (+), 1 changed (~), 2 removed (-), 32 unchanged (=)
-0 object files added, 1 removed
-Removed files:
+2 symbols added (+), 1 changed (~), 3 removed (-), 32 unchanged (=)
+1 object files added, 0 removed
+Added files:
   third_party/ffmpeg/libffmpeg_internal.a/fft_fixed.o
 
-Showing 38 symbols with total size: -10 bytes
-.text=-10 bytes  .rodata=0 bytes    other=0 bytes    total=-10 bytes
+Showing 38 symbols with total size: 10 bytes
+.text=10 bytes   .rodata=0 bytes    other=0 bytes    total=10 bytes
 Number of object files: 10
 
 First columns are: running total, type, size
-~      -10 t@0x28d900   size=-10  padding=0  size_without_padding=-10
+~       10 t@0x28d900   size=10  padding=0  size_without_padding=10
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=startup._GLOBAL__sub_I_page_allocator.cc
-=      -10 r@0x284e364  size=0  padding=0  size_without_padding=0
+=       10 r@0x284e364  size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
-=      -10 r@Group      size=0  padding=0  size_without_padding=0  count=2
+=       10 r@Group      size=0  padding=0  size_without_padding=0  count=2
                source_path= 	object_path=
                is_anonymous=0  name=** merge strings
-=      -10 t@Group      size=0  padding=0  size_without_padding=0  count=2
+=       10 t@Group      size=0  padding=0  size_without_padding=0  count=2
                source_path=None 	object_path=None
                is_anonymous=0  name=** symbol gaps
-=      -10 d@0x2cd84e0  size=0  padding=0  size_without_padding=0
+=       10 d@0x2cd84e0  size=0  padding=0  size_without_padding=0
                source_path= 	object_path=third_party/gvr-android-sdk/libgvr_shim_static_arm.a/libcontroller_api_impl.a_controller_api_impl.o
                is_anonymous=0  name=.Lswitch.table.45
-=      -10 d@0x2c176f0  size=0  padding=0  size_without_padding=0
+=       10 d@0x2c176f0  size=0  padding=0  size_without_padding=0
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=ChromeMainDelegate [vtable]
-=      -10 d@0x2cd8500  size=0  padding=0  size_without_padding=0
+=       10 d@0x2cd8500  size=0  padding=0  size_without_padding=0
                source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
                is_anonymous=0  name=ChromeMainDelegateAndroid [vtable]
-=      -10 r@0x284e370  size=0  padding=0  size_without_padding=0
+=       10 r@0x284e370  size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=Name
-=      -10 d@0x2de70a0  size=0  padding=0  size_without_padding=0
+=       10 d@0x2de70a0  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=1  name=base::android::g_renderer_histogram_code
-=      -10 r@0x28f3480  size=0  padding=0  size_without_padding=0
+=       10 r@0x28f3480  size=0  padding=0  size_without_padding=0
                source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
                is_anonymous=1  name=blink::CSSValueKeywordsHash::findValueImpl::value_word_list
                           full_name=blink::CSSValueKeywordsHash::findValueImpl(char const*, unsigned int)::value_word_list
-=      -10 t@0x2a0020   size=0  padding=0  size_without_padding=0
+=       10 t@0x2a0020   size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=blink::ContiguousContainerBase::ContiguousContainerBase
                           full_name=blink::ContiguousContainerBase::ContiguousContainerBase(blink::ContiguousContainerBase&&)
-=      -10 t@0x2a0000   size=0  padding=0  size_without_padding=0
+=       10 t@0x2a0000   size=0  padding=0  size_without_padding=0
                source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
                is_anonymous=0  name=blink::ContiguousContainerBase::shrinkToFit
                           full_name=blink::ContiguousContainerBase::shrinkToFit()
-=      -10 t@0x2a0010   size=0  padding=0  size_without_padding=0
+=       10 t@0x2a0010   size=0  padding=0  size_without_padding=0
                source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
                is_anonymous=0  name=blink::ContiguousContainerBase::shrinkToFit [clone .part.1234] [clone .isra.2]
                           full_name=blink::ContiguousContainerBase::shrinkToFit() [clone .part.1234] [clone .isra.2]
-=      -10 t@0x2a1000   size=0  padding=0  size_without_padding=0
+=       10 t@0x2a1000   size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=1  name=blink::PaintChunker::releasePaintChunks [clone .part.1]
                           full_name=blink::PaintChunker::releasePaintChunks() [clone .part.1]
-=      -10 d@0x2c17740  size=0  padding=0  size_without_padding=0
+=       10 d@0x2c17740  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=chrome::mojom::FieldTrialRecorderProxy [vtable]
-=      -10 d@0x2c17728  size=0  padding=0  size_without_padding=0
+=       10 d@0x2c17728  size=0  padding=0  size_without_padding=0
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=chrome::mojom::FieldTrialRecorderRequestValidator [vtable]
-=      -10 r@0x284e398  size=0  padding=0  size_without_padding=0
+=       10 r@0x284e398  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=chrome::mojom::FilePatcher::Name_
-=      -10 t@0x28d964   size=0  padding=0  size_without_padding=0
+=       10 t@0x28d964   size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=extFromUUseMapping
                           full_name=extFromUUseMapping(signed char, unsigned int, int)
-=      -10 t@0x28d98a   size=0  padding=0  size_without_padding=0
+=       10 t@0x28d98a   size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=extFromUUseMapping
                           full_name=extFromUUseMapping(aj, int)
-=      -10 d@0x2de7000  size=0  padding=0  size_without_padding=0
+=       10 d@0x2de7000  size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=google::protobuf::internal::pLinuxKernelCmpxchg
-=      -10 d@0x2de7004  size=0  padding=0  size_without_padding=0
+=       10 d@0x2de7004  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=google::protobuf::internal::pLinuxKernelMemoryBarrier
-=      -10 r@0x28f3450  size=0  padding=0  size_without_padding=0
+=       10 r@0x28f3450  size=0  padding=0  size_without_padding=0
                source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
                is_anonymous=1  name=kAnimationFrameTimeHistogramClassPath
-=      -10 d@0x2cd8550  size=0  padding=0  size_without_padding=0
+=       10 d@0x2cd8550  size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=kMethodsAnimationFrameTimeHistogram
-=      -10 d@0x2cd84f0  size=0  padding=0  size_without_padding=0
+=       10 d@0x2cd84f0  size=0  padding=0  size_without_padding=0
                source_path= 	object_path=third_party/gvr-android-sdk/libgvr_shim_static_arm.a/libport_android_jni.a_jni_utils.o
                is_anonymous=1  name=kSystemClassPrefixes
-=      -10 d@0x2cd8538  size=0  padding=0  size_without_padding=0
+=       10 d@0x2cd8538  size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=mojo::MessageReceiver [vtable]
-=      -10 d@0x2de7008  size=0  padding=0  size_without_padding=0
+=       10 d@0x2de7008  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=rel._ZN4base7androidL22kBaseRegisteredMethodsE
-=      -10 d@0x2de70a4  size=0  padding=0  size_without_padding=0
+=       10 d@0x2de70a4  size=0  padding=0  size_without_padding=0
                source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
                is_anonymous=0  name=rel.local._ZN4base7android12_GLOBAL__N_124g_library_version_numberE
-=      -10 t@0x28f1c8   size=0  padding=0  size_without_padding=0
+=       10 t@0x28f1c8   size=0  padding=0  size_without_padding=0
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=startup._GLOBAL__sub_I_SkDeviceProfile.cpp
-=      -10 t@0x28f1e0   size=0  padding=0  size_without_padding=0
+=       10 t@0x28f1e0   size=0  padding=0  size_without_padding=0
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=startup._GLOBAL__sub_I_SkDiscardableMemoryPool.cpp
-=      -10 t@0x28d910   size=0  padding=0  size_without_padding=0
+=       10 t@0x28d910   size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=startup._GLOBAL__sub_I_bbr_sender.cc
-=      -10 t@0x28d948   size=0  padding=0  size_without_padding=0
+=       10 t@0x28d948   size=0  padding=0  size_without_padding=0
                source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
                is_anonymous=0  name=startup._GLOBAL__sub_I_pacing_sender.cc
-=      -10 t@0x28f000   size=0  padding=0  size_without_padding=0
+=       10 t@0x28f000   size=0  padding=0  size_without_padding=0
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=ucnv_extMatchFromU
                           full_name=ucnv_extMatchFromU(int const*, int, unsigned short const*, int, unsigned short const*, int, unsigned int*, signed char, signed char)
--      -10 b@0x0        size=-262144  padding=0  size_without_padding=-262144
++       10 b@0x0        size=262144  padding=0  size_without_padding=262144
                source_path=third_party/fft_float.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_float.o
                is_anonymous=0  name=ff_cos_131072
--      -10 b@0x0        size=-131072  padding=0  size_without_padding=-131072
++       10 b@0x0        size=131072  padding=0  size_without_padding=131072
                source_path=third_party/fft_fixed.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_fixed.o
                is_anonymous=0  name=ff_cos_131072_fixed
-+      -10 b@0x2dffe80  size=200  padding=196  size_without_padding=4
+-       10 b@0x2dffe80  size=-200  padding=-196  size_without_padding=-4
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=SaveHistogram::atomic_histogram_pointer
                           full_name=SaveHistogram(_JNIEnv*, base::android::JavaParamRef<_jobject*> const&, base::android::JavaParamRef<_jstring*> const&, base::android::JavaParamRef<_jlongArray*> const&, int)::atomic_histogram_pointer
-+      -10 b@0x2dffda0  size=28  padding=0  size_without_padding=28
+-       10 b@0x2dffda0  size=-28  padding=0  size_without_padding=-28
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=0  name=g_chrome_content_browser_client
-+      -10 b@0x2dffe84  size=4  padding=0  size_without_padding=4
+-       10 b@0x2dffe84  size=-4  padding=0  size_without_padding=-4
                source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
                is_anonymous=1  name=g_AnimationFrameTimeHistogram_clazz
-=      -10 b@0x0        size=0  padding=0  size_without_padding=0
+=       10 b@0x0        size=0  padding=0  size_without_padding=0
                source_path=third_party/fft_float.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_float.o
                is_anonymous=0  name=ff_cos_65536