Add icudt.dll for Windows

1. Generate and add windows/icudt.dll with the procedure outlined
in README.chromium. It uses a out-of-tree copy of the upstream ICU
along with our custom-built icudtl.dat and a locally modified version
of makedata.mak.

We used to have a separate build/ directory for VS solution/project files
to build icudtl.dll. Maintaining them is rather cumbersom now that we
want to update our ICU (major version changes) more frequently. 

Note that icudt.dll is not used by default (icu_use_data_file_flag=1). 
The GN build still uses it by default and we should not break that build.

2. Add scripts/make_mac_assembly.sh to simplify the generation of the icu
data assembly source file for Mac.

3. Update README.chromium accordingly.

This CL was uploaded and reviewed at 

https://codereview.chromium.org/255943004/

Due to a malfunction at codereview.chromium.org, I'm landing this CL 
manually in two parts. 
This check-in is the 2nd part of the CL dealing with #2 and #3
above.

BUG=132145
TEST=None until icu is rolled to this version.


git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/icu52@266602 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

1 files changed, 23 insertions, 22 deletions

diff --git a/README.chromium b/README.chromium
index 022c846..d654a82 100644
--- a/README.chromium
+++ b/README.chromium
@@ -145,8 +145,7 @@ This directory contains the source code of ICU 52.1 for C/C++
   - patches/data.build.patch :
       Remove unnecessary resources : invuca, unames, collator source, stringprep
   - patches/data.build.win.patch :
-      Windows-only data build patch. Add a new target DATALIB to makedata.mak
-  - add an empty file (stubdatabuilt.txt) to source/stubdata
+      Windows-only data build patch.
 
 9. Pre-built data files are checked in with the following steps on Linux:
 
@@ -172,32 +171,15 @@ This directory contains the source code of ICU 52.1 for C/C++
       {BUILD_DIR_ROOT}/data/out/tmp and copied to the above location with a
       version number (52) dropped.
 
-    - windows/icudt.dll : With icudt52l.dat in place, all the patches applied
-      and header files moved (#11 below), generated by building icudt_build
-      project of build/icudt_build.sln on Windows. icudt52.dll is
-      generated in bin/{Release,Debug} and copied to windows/icudt.dll
-      and checked in. Note that we drop the version number ('52') from the
-      dll name to avoind having to update our build scripts/configuration
-      files everytime ICU is upgraded to a new version.
 
     - {mac,linux}/icudtl_dat.S : Built on Linux with all the
       patches above (except android/brkitr.patch) applied and checked in.
       This file will be generated in {BUILD_DIR_ROOT}/data/out/tmp as
       icudt52l_dat.S, but '52' is dropped while copying.
 
-      mac/icudtl_dat.S is identical to linux/icudtl_dat.S. It's made
-      by changing the header portion of the Linux version to read as following
-      (no leading whitespace) :
-
-          .globl _icudt52_dat
-          #ifdef U_HIDE_DATA_SYMBOL
-                 .private_extern _icudt52_dat
-          #endif
-                 .data
-                 .const
-                 .align 4
-          _icudt52_dat:
-
+      mac/icudtl_dat.S is identical to linux/icudtl_dat.S except for
+      the header portion. With "linux/icudtl_dat.S" in its place, 
+      run scripts/make_mac_assembly.sh to generate it.
 
     - android/icudtl_dat.S : Built on Linux with all the patches above and
       android/brkitr.patch applied and android/patch_locale.sh executed.
@@ -207,6 +189,25 @@ This directory contains the source code of ICU 52.1 for C/C++
       {BUILD_DIR_ROOT}/data/out/tmp along with icudt52l_dat.S and
       copied to the above location with '52' dropped in its name.
 
+    - windows/icudt.dll (by default, we set icu_use_icu_data_flag to 1
+      and don't use this file.) 
+
+      a. check out a clean copy of icu52  from the upstream on Windows
+         outside the Chrome tree.
+
+        $ svn export --native-eol LF http://source.icu-project.org/repos/icu/icu/tags/release-52-1 ${SEPARATE_ICU_ROOT}/icu52
+
+      b. copy ${CHROME_ICU_ROOT}/source/data/in/icudtl.dat to 
+         ${SEPARATE_ICU_ROOT}/source/data/in/icudt52l.dat
+      c. copy ${CHROME_ICU_ROOT}/source/data/makedata.mak to
+         ${SEPARATE_ICU_ROOT}/source/data/makedata.mak
+      c. In Visual Studio, open source/allinone/allinone.sln solution
+         in ${SEPARATE_ICU_ROOT}
+      d. Build 'makedata' target 
+      e. icudt52.dll will be generated in ${SEPARATE_ICU_ROOT}/bin
+      f. Copy that icudt52.dll to ${CHROME_ICU_ROOT}/windows/icudt.dll 
+         and check that in.
+
 
 10. Change export of U_ICUDATA_ENTRY_POINT from U_IMPORT to U_EXPORT.
     - patches/declspec.patch