Update Windows build instructions

The Windows build instructions for Chromium leads many people to assume
that the --ide command is required. This change makes it clearer that it
is optional, and also expands on how to use the alternatives.

This also changes the recommend invocation of "gclient sync" to add
"-D".

Tested with https://markdownlivepreview.com/

Change-Id: Ia341f3021c320a4cf7a7071fb96f0464078baf3f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2444450
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Auto-Submit: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813438}

docs/windows_build_instructions.md

@@ -178,58 +178,6 @@ $ gn gen out/Default
   operating system and CPU.
 * For more info on GN, run `gn help` on the command line or read the [quick
   start guide](https://gn.googlesource.com/gn/+/master/docs/quick_start.md).
-
-### Using the Visual Studio IDE
-
-If you want to use the Visual Studio IDE, use the `--ide` command line
-argument to `gn gen` when you generate your output directory (as described on
-the [get the code](https://dev.chromium.org/developers/how-tos/get-the-code)
-page):
-
-```shell
-$ gn gen --ide=vs out\Default
-$ devenv out\Default\all.sln
-```
-
-GN will produce a file `all.sln` in your build directory. It will internally
-use Ninja to compile while still allowing most IDE functions to work (there is
-no native Visual Studio compilation mode). If you manually run "gen" again you
-will need to resupply this argument, but normally GN will keep the build and
-IDE files up to date automatically when you build.
-
-The generated solution will contain several thousand projects and will be very
-slow to load. Use the `--filters` argument to restrict generating project files
-for only the code you're interested in. Although this will also limit what
-files appear in the project explorer, debugging will still work and you can
-set breakpoints in files that you open manually. A minimal solution that will
-let you compile and run Chrome in the IDE but will not show any source files
-is:
-
-```
-$ gn gen --ide=vs --filters=//chrome --no-deps out\Default
-```
-
-You can selectively add other directories you care about to the filter like so:
-`--filters=//chrome;//third_party/WebKit/*;//gpu/*`.
-
-There are other options for controlling how the solution is generated, run `gn
-help gen` for the current documentation.
-
-By default when you start debugging in Visual Studio the debugger will only
-attach to the main browser process. To debug all of Chrome, install
-[Microsoft's Child Process Debugging Power Tool](https://blogs.msdn.microsoft.com/devops/2014/11/24/introducing-the-child-process-debugging-power-tool/).
-You will also need to run Visual Studio as administrator, or it will silently
-fail to attach to some of Chrome's child processes.
-
-It is also possible to debug and develop Chrome in Visual Studio without a
-solution file. Simply "open" your chrome.exe binary with
-`File->Open->Project/Solution`, or from a Visual Studio command prompt like
-so: `devenv /debugexe out\Debug\chrome.exe <your arguments>`. Many of Visual
-Studio's code editing features will not work in this configuration, but by
-installing the [VsChromium Visual Studio Extension](https://chromium.github.io/vs-chromium/)
-you can get the source code to appear in the solution explorer window along
-with other useful features such as code search.
-
 ### Faster builds
 
 * Reduce file system overhead by excluding build directories from
@@ -418,7 +366,7 @@ To update an existing checkout, you can run
 
 ```shell
 $ git rebase-update
-$ gclient sync
+$ gclient sync -D
 ```
 
 The first command updates the primary Chromium source repository and rebases
@@ -426,5 +374,70 @@ any of your local branches on top of tip-of-tree (aka the Git branch `origin/mas
 If you don't want to use this script, you can also just use `git pull` or
 other common Git commands to update the repo.
 
-The second command syncs the subrepositories to the appropriate versions and
-re-runs the hooks as needed.
+The second command syncs the subrepositories to the appropriate versions,
+deleting those that are no longer needed, and re-runs the hooks as needed.
+
+### Editing and Debugging With the Visual Studio IDE
+
+You can use the Visual Studio IDE to edit and debug Chrome, with or without
+Intellisense support.
+
+#### Using Visual Studio Intellisense
+
+If you want to use Visual Studio Intellisense when developing Chromium, use the
+`--ide` command line argument to `gn gen` when you generate your output
+directory (as described on the [get the code](https://dev.chromium.org/developers/how-tos/get-the-code)
+page):
+
+```shell
+$ gn gen --ide=vs out\Default
+$ devenv out\Default\all.sln
+```
+
+GN will produce a file `all.sln` in your build directory. It will internally
+use Ninja to compile while still allowing most IDE functions to work (there is
+no native Visual Studio compilation mode). If you manually run "gen" again you
+will need to resupply this argument, but normally GN will keep the build and
+IDE files up to date automatically when you build.
+
+The generated solution will contain several thousand projects and will be very
+slow to load. Use the `--filters` argument to restrict generating project files
+for only the code you're interested in. Although this will also limit what
+files appear in the project explorer, debugging will still work and you can
+set breakpoints in files that you open manually. A minimal solution that will
+let you compile and run Chrome in the IDE but will not show any source files
+is:
+
+```
+$ gn gen --ide=vs --filters=//chrome --no-deps out\Default
+```
+
+You can selectively add other directories you care about to the filter like so:
+`--filters=//chrome;//third_party/WebKit/*;//gpu/*`.
+
+There are other options for controlling how the solution is generated, run `gn
+help gen` for the current documentation.
+
+#### Using Visual Studio without Intellisense
+
+It is also possible to debug and develop Chrome in Visual Studio without the
+overhead of a multi-project solution file. Simply "open" your chrome.exe binary
+with `File->Open->Project/Solution`, or from a Visual Studio command prompt like
+so: `devenv /debugexe out\Debug\chrome.exe <your arguments>`. Many of Visual
+Studio's code exploration features will not work in this configuration, but by
+installing the [VsChromium Visual Studio Extension](https://chromium.github.io/vs-chromium/)
+you can get the source code to appear in the solution explorer window along
+with other useful features such as code search. You can add multiple executables
+of interest (base_unittests.exe, browser_tests.exe) to your solution with
+`File->Add->Existing Project...` and change which one will be debugged by
+right-clicking on them in `Solution Explorer` and selecting `Set as Startup
+Project`. You can also change their properties, including command line
+arguments, by right-clicking on them in `Solution Explorer` and selecting
+`Properties`.
+
+By default when you start debugging in Visual Studio the debugger will only
+attach to the main browser process. To debug all of Chrome, install
+[Microsoft's Child Process Debugging Power Tool](https://blogs.msdn.microsoft.com/devops/2014/11/24/introducing-the-child-process-debugging-power-tool/).
+You will also need to run Visual Studio as administrator, or it will silently
+fail to attach to some of Chrome's child processes.
+