supersize: Update README.md with technical details.

tools/binary_size/libsupersize/testdata/FullDescription.golden

Index: tools/binary_size/libsupersize/testdata/FullDescription.golden
diff --git a/tools/binary_size/libsupersize/testdata/FullDescription.golden b/tools/binary_size/libsupersize/testdata/FullDescription.golden
index 042ec49b7308355418104268277a23a220e2b419..f1b1a14bc626df37e3c20feaca9fb539ce8c204c 100644
--- a/tools/binary_size/libsupersize/testdata/FullDescription.golden
+++ b/tools/binary_size/libsupersize/testdata/FullDescription.golden
@@ -7,37 +7,37 @@ Metadata:
     gn_args=var1=true var2="foo"
     map_file_name=../test.map
 
-Section Sizes (Total=43,785,380 bytes):
-    .bss: 1,300,456 bytes (not included in totals)
-    .data: 101,768 bytes (0.2%)
-    .data.rel.ro: 1,065,224 bytes (2.4%)
-    .data.rel.ro.local: 790,024 bytes (1.8%)
-    .rodata: 5,927,652 bytes (13.5%)
-    .text: 35,900,712 bytes (82.0%)
+Section Sizes (Total=41.8mb (43785380 bytes)):
+    .bss: 1.24mb (1300456 bytes) (not included in totals)
+    .data: 99.4kb (101768 bytes) (0.2%)
+    .data.rel.ro: 1.02mb (1065224 bytes) (2.4%)
+    .data.rel.ro.local: 771kb (790024 bytes) (1.8%)
+    .rodata: 5.65mb (5927652 bytes) (13.5%)
+    .text: 34.2mb (35900712 bytes) (82.0%)
 
 Other section sizes:
-    .ARM.attributes: 60 bytes
-    .ARM.exidx: 1,536,456 bytes
-    .ARM.extab: 183,632 bytes
-    .dynamic: 304 bytes
-    .dynstr: 4,025 bytes
-    .dynsym: 6,496 bytes
-    .fini_array: 8 bytes
-    .gnu.version: 812 bytes
-    .gnu.version_d: 28 bytes
-    .gnu.version_r: 96 bytes
-    .got: 42,956 bytes
-    .hash: 2,684 bytes
-    .init_array: 8 bytes
-    .interp: 19 bytes
-    .note.gnu.build-id: 36 bytes
-    .note.gnu.gold-version: 28 bytes
-    .plt: 4,244 bytes
-    .rel.dyn: 2,655,384 bytes
-    .rel.plt: 2,816 bytes
-    .shstrtab: 436 bytes
-    .strtab: 34,841,854 bytes
-    .symtab: 17,166,112 bytes
+    .ARM.attributes: 60 bytes (60 bytes)
+    .ARM.exidx: 1.47mb (1536456 bytes)
+    .ARM.extab: 179kb (183632 bytes)
+    .dynamic: 304 bytes (304 bytes)
+    .dynstr: 3.93kb (4025 bytes)
+    .dynsym: 6.34kb (6496 bytes)
+    .fini_array: 8 bytes (8 bytes)
+    .gnu.version: 812 bytes (812 bytes)
+    .gnu.version_d: 28 bytes (28 bytes)
+    .gnu.version_r: 96 bytes (96 bytes)
+    .got: 41.9kb (42956 bytes)
+    .hash: 2.62kb (2684 bytes)
+    .init_array: 8 bytes (8 bytes)
+    .interp: 19 bytes (19 bytes)
+    .note.gnu.build-id: 36 bytes (36 bytes)
+    .note.gnu.gold-version: 28 bytes (28 bytes)
+    .plt: 4.14kb (4244 bytes)
+    .rel.dyn: 2.53mb (2655384 bytes)
+    .rel.plt: 2.75kb (2816 bytes)
+    .shstrtab: 436 bytes (436 bytes)
+    .strtab: 33.2mb (34841854 bytes)
+    .symtab: 16.4mb (17166112 bytes)
 
 Section r: has 100.0% of 5927652 bytes accounted for from 9 symbols. 0 bytes are unaccounted for.
 * Padding accounts for 11 bytes (0.0%)
@@ -56,8 +56,8 @@ Section t: has 100.0% of 35900712 bytes accounted for from 18 symbols. 0 bytes a
 * Contains 5 aliases, mapped to 2 unique addresses (60 bytes)
 * 1 symbols have shared ownership (12 bytes)
 
-Showing 43 symbols (42 unique) with total pss: 44309900 bytes
-.text=34.2mb     .rodata=5.65mb     other=2.37mb     total=42.3mb
+Showing 43 symbols (42 unique) with total pss: 43785380 bytes
+.text=34.2mb     .rodata=5.65mb     .data*=1.87mb     .bss=512kb      total=41.8mb
 Number of object files: 10
 
 Index, Running Total, Section@Address, PSS
@@ -79,7 +79,7 @@ Index, Running Total, Section@Address, PSS
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
              flags={}  name=extFromUUseMapping
                   full_name=extFromUUseMapping(aj, int)
-5)   35830930 (80.9%) t@Group      pss=35830760  padding=35830760  size_without_padding=0  count=3
+5)   35830930 (81.8%) t@Group      pss=35830760  padding=35830760  size_without_padding=0  count=3
              source_path= 	object_path=
              flags={}  name=** symbol gaps
 > 0)       5718 (0.0%)  t@0x28f000   pss=5718  padding=5718  size_without_padding=0
@@ -91,17 +91,17 @@ Index, Running Total, Section@Address, PSS
 > 2)   35830760 (100.0%) t@0x24ca628  pss=35821002  padding=35821002  size_without_padding=0
                source_path= 	object_path=
                flags={}  name=** symbol gap 2 (end of section)
-6)   35831378 (80.9%) t@0x28f000   pss=448  padding=0  size_without_padding=448
+6)   35831378 (81.8%) t@0x28f000   pss=448  padding=0  size_without_padding=448
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen}  name=ucnv_extMatchFromU
                   full_name=ucnv_extMatchFromU(int const*, int, unsigned short const*, int, unsigned short const*, int, unsigned int*, signed char, signed char)
-7)   35831406 (80.9%) t@0x28f1c8   pss=28  padding=8  size_without_padding=20
+7)   35831406 (81.8%) t@0x28f1c8   pss=28  padding=8  size_without_padding=20
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={startup,gen}  name=_GLOBAL__sub_I_SkDeviceProfile.cpp
-8)   35900530 (81.0%) t@0x28f1e0   pss=69124  padding=4  size_without_padding=69120
+8)   35900530 (82.0%) t@0x28f1e0   pss=69124  padding=4  size_without_padding=69120
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={unlikely,gen}  name=foo_bar
-9)   35900558 (81.0%) t@Group      pss=28  padding=32  size_without_padding=28  count=2
+9)   35900558 (82.0%) t@Group      pss=28  padding=32  size_without_padding=28  count=2
              source_path= 	object_path=
              flags={}  name=blink::ContiguousContainerBase::shrinkToFit
                   full_name=blink::ContiguousContainerBase::shrinkToFit()
@@ -113,27 +113,27 @@ Index, Running Total, Section@Address, PSS
                source_path=third_party/{shared}/2 	object_path=third_party/{shared}/2
                flags={3 aliases}  name=blink::ContiguousContainerBase::shrinkToFit [clone .part.1234] [clone .isra.2]
                     full_name=blink::ContiguousContainerBase::shrinkToFit() [clone .part.1234] [clone .isra.2]
-10)  35900582 (81.0%) t@0x2a0000   pss=24  padding=32  size_without_padding=16
+10)  35900582 (82.0%) t@0x2a0000   pss=24  padding=32  size_without_padding=16
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen,2 aliases}  name=BazAlias
                   full_name=BazAlias(bool)
-11)  35900586 (81.0%) t@0x2a0010   pss=4  padding=0  size_without_padding=12
+11)  35900586 (82.0%) t@0x2a0010   pss=4  padding=0  size_without_padding=12
              source_path=third_party/fft_float.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_float.o
              flags={3 aliases}  name=FooAlias
                   full_name=FooAlias()
-12)  35900590 (81.0%) t@0x2a0010   pss=4  padding=0  size_without_padding=12
+12)  35900590 (82.0%) t@0x2a0010   pss=4  padding=0  size_without_padding=12
              source_path=third_party/fft_float.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_float.o
              flags={3 aliases}  name=BarAlias
                   full_name=BarAlias()
-13)  35900618 (81.0%) t@0x2a0020   pss=28  padding=4  size_without_padding=24
+13)  35900618 (82.0%) t@0x2a0020   pss=28  padding=4  size_without_padding=24
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={}  name=blink::ContiguousContainerBase::ContiguousContainerBase
                   full_name=blink::ContiguousContainerBase::ContiguousContainerBase(blink::ContiguousContainerBase&&)
-14)  35900712 (81.0%) t@0x2a1000   pss=94  padding=0  size_without_padding=94
+14)  35900712 (82.0%) t@0x2a1000   pss=94  padding=0  size_without_padding=94
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={anon}  name=blink::PaintChunker::releasePaintChunks [clone .part.1]
                   full_name=blink::PaintChunker::releasePaintChunks() [clone .part.1]
-15)  38542106 (87.0%) r@Group      pss=2641394  padding=352  size_without_padding=2641042  count=2
+15)  38542106 (88.0%) r@Group      pss=2641394  padding=352  size_without_padding=2641042  count=2
              source_path= 	object_path=
              flags={}  name=** merge strings
 > 0)    1965409 (74.4%) r@0x266e600  pss=1965409  padding=0  size_without_padding=1965409
@@ -142,7 +142,7 @@ Index, Running Total, Section@Address, PSS
 > 1)    2641394 (100.0%) r@0x284e518  pss=675985  padding=352  size_without_padding=675633
                source_path= 	object_path=
                flags={}  name=** merge strings
-16)  41828221 (94.4%) r@Group      pss=3286115  padding=3286115  size_without_padding=0  count=2
+16)  41828221 (95.5%) r@Group      pss=3286115  padding=3286115  size_without_padding=0  count=2
              source_path= 	object_path=
              flags={}  name=** symbol gaps
 > 0)          3 (0.0%)  r@0x284e364  pss=3  padding=3  size_without_padding=0
@@ -151,82 +151,82 @@ Index, Running Total, Section@Address, PSS
 > 1)    3286115 (100.0%) r@0x2c158e4  pss=3286112  padding=3286112  size_without_padding=0
                source_path= 	object_path=
                flags={}  name=** symbol gap 3 (end of section)
-17)  41828229 (94.4%) r@0x284e364  pss=8  padding=0  size_without_padding=8
+17)  41828229 (95.5%) r@0x284e364  pss=8  padding=0  size_without_padding=8
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
-18)  41828273 (94.4%) r@0x284e370  pss=44  padding=4  size_without_padding=40
+18)  41828273 (95.5%) r@0x284e370  pss=44  padding=4  size_without_padding=40
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
              flags={}  name=Name
-19)  41828305 (94.4%) r@0x284e398  pss=32  padding=0  size_without_padding=32
+19)  41828305 (95.5%) r@0x284e398  pss=32  padding=0  size_without_padding=32
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={}  name=chrome::mojom::FilePatcher::Name_
-20)  41828360 (94.4%) r@0x28f3450  pss=55  padding=7  size_without_padding=48
+20)  41828360 (95.5%) r@0x28f3450  pss=55  padding=7  size_without_padding=48
              source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
              flags={anon}  name=kAnimationFrameTimeHistogramClassPath
-21)  41828364 (94.4%) r@0x28f3480  pss=4  padding=0  size_without_padding=4
+21)  41828364 (95.5%) r@0x28f3480  pss=4  padding=0  size_without_padding=4
              source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
              flags={anon}  name=blink::CSSValueKeywordsHash::findValueImpl::value_word_list
                   full_name=blink::CSSValueKeywordsHash::findValueImpl(char const*, unsigned int)::value_word_list
-22)  41828420 (94.4%) d@0x2c176f0  pss=56  padding=0  size_without_padding=56
+22)  41828420 (95.5%) d@0x2c176f0  pss=56  padding=0  size_without_padding=56
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen}  name=ChromeMainDelegate [vtable]
-23)  41828444 (94.4%) d@0x2c17728  pss=24  padding=0  size_without_padding=24
+23)  41828444 (95.5%) d@0x2c17728  pss=24  padding=0  size_without_padding=24
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen}  name=chrome::mojom::FieldTrialRecorder [vtable]
-24)  42618348 (96.2%) d@0x2c17740  pss=789904  padding=0  size_without_padding=789904
+24)  42618348 (97.3%) d@0x2c17740  pss=789904  padding=0  size_without_padding=789904
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={}  name=chrome::mojom::FieldTrialRecorderProxy [vtable]
-25)  42618380 (96.2%) d@0x2cd84e0  pss=32  padding=16  size_without_padding=16
+25)  42618380 (97.3%) d@0x2cd84e0  pss=32  padding=16  size_without_padding=16
              source_path= 	object_path=third_party/gvr-android-sdk/libgvr_shim_static_arm.a/libcontroller_api_impl.a_controller_api_impl.o
              flags={}  name=.Lswitch.table.45
-26)  42618388 (96.2%) d@0x2cd84f0  pss=8  padding=0  size_without_padding=8
+26)  42618388 (97.3%) d@0x2cd84f0  pss=8  padding=0  size_without_padding=8
              source_path= 	object_path=third_party/gvr-android-sdk/libgvr_shim_static_arm.a/libport_android_jni.a_jni_utils.o
              flags={anon}  name=kSystemClassPrefixes
-27)  42618444 (96.2%) d@0x2cd8500  pss=56  padding=0  size_without_padding=56
+27)  42618444 (97.3%) d@0x2cd8500  pss=56  padding=0  size_without_padding=56
              source_path=third_party/paint.cc 	object_path=third_party/WebKit.a/PaintChunker.o
              flags={}  name=ChromeMainDelegateAndroid [vtable]
-28)  42618468 (96.2%) d@0x2cd8538  pss=24  padding=0  size_without_padding=24
+28)  42618468 (97.3%) d@0x2cd8538  pss=24  padding=0  size_without_padding=24
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
              flags={}  name=mojo::MessageReceiver [vtable]
-29)  42618480 (96.2%) d@0x2cd8550  pss=12  padding=0  size_without_padding=12
+29)  42618480 (97.3%) d@0x2cd8550  pss=12  padding=0  size_without_padding=12
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
              flags={}  name=kMethodsAnimationFrameTimeHistogram
-30)  43683612 (98.6%) d@0x2ddc608  pss=1065132  padding=1065132  size_without_padding=0
+30)  43683612 (99.8%) d@0x2ddc608  pss=1065132  padding=1065132  size_without_padding=0
              source_path= 	object_path=
              flags={}  name=** symbol gap 3 (end of section)
-31)  43683616 (98.6%) d@0x2de7000  pss=4  padding=0  size_without_padding=4
+31)  43683616 (99.8%) d@0x2de7000  pss=4  padding=0  size_without_padding=4
              source_path=base/page_allocator.cc 	object_path=base/base/page_allocator.o
              flags={}  name=google::protobuf::internal::pLinuxKernelCmpxchg
-32)  43683620 (98.6%) d@0x2de7004  pss=4  padding=0  size_without_padding=4
+32)  43683620 (99.8%) d@0x2de7004  pss=4  padding=0  size_without_padding=4
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={}  name=google::protobuf::internal::pLinuxKernelMemoryBarrier
-33)  43683772 (98.6%) d@0x2de7008  pss=152  padding=0  size_without_padding=152
+33)  43683772 (99.8%) d@0x2de7008  pss=152  padding=0  size_without_padding=152
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={rel}  name=base::android::kBaseRegisteredMethods
-34)  43683776 (98.6%) d@0x2de70a0  pss=4  padding=0  size_without_padding=4
+34)  43683776 (99.8%) d@0x2de70a0  pss=4  padding=0  size_without_padding=4
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={anon}  name=base::android::g_renderer_histogram_code
-35)  43683780 (98.6%) d@0x2de70a4  pss=4  padding=0  size_without_padding=4
+35)  43683780 (99.8%) d@0x2de70a4  pss=4  padding=0  size_without_padding=4
              source_path=third_party/container.c 	object_path=third_party/WebKit.a/ContiguousContainer.o
              flags={anon,rel.loc}  name=base::android::g_library_version_number
-36)  43785380 (98.8%) d@0x2dffd88  pss=101600  padding=101600  size_without_padding=0
+36)  43785380 (100.0%) d@0x2dffd88  pss=101600  padding=101600  size_without_padding=0
              source_path= 	object_path=
              flags={}  name=** symbol gap 3 (end of section)
-37)  43785380 (98.8%) b@0x0        pss=262144  padding=0  size_without_padding=262144
+37)  43785380 (100.0%) b@0x0        pss=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
              flags={}  name=ff_cos_131072
-38)  43785380 (98.8%) b@0x0        pss=131072  padding=0  size_without_padding=131072
+38)  43785380 (100.0%) b@0x0        pss=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
              flags={}  name=ff_cos_131072_fixed
-39)  43785380 (98.8%) b@0x0        pss=131072  padding=0  size_without_padding=131072
+39)  43785380 (100.0%) b@0x0        pss=131072  padding=0  size_without_padding=131072
              source_path=third_party/fft_float.cc 	object_path=third_party/ffmpeg/libffmpeg_internal.a/fft_float.o
              flags={}  name=ff_cos_65536
-40)  43785380 (98.8%) b@0x2dffda0  pss=28  padding=0  size_without_padding=28
+40)  43785380 (100.0%) b@0x2dffda0  pss=28  padding=0  size_without_padding=28
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen}  name=g_chrome_content_browser_client
-41)  43785380 (98.8%) b@0x2dffe80  pss=200  padding=196  size_without_padding=4
+41)  43785380 (100.0%) b@0x2dffe80  pss=200  padding=196  size_without_padding=4
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={gen}  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
-42)  43785380 (98.8%) b@0x2dffe84  pss=4  padding=0  size_without_padding=4
+42)  43785380 (100.0%) b@0x2dffe84  pss=4  padding=0  size_without_padding=4
              source_path=third_party/icu/ucnv_ext.c 	object_path=third_party/icu/icuuc/ucnv_ext.o
              flags={anon,gen}  name=g_AnimationFrameTimeHistogram_clazz