Make --watchfs a common command option.

Adding an options parameter to DiffAwareness#getCurrentView seems like the
simplest way to achieve that.

Alternatives considered:
1. Making the diff awareness modules stateful. However, I did not want to do so
as I've also been working on improving the module API to reduce state, or at
least to have a proper lifecycle management for any necessary state.

2. Making the watchFs flag a constructor parameter. However, that would also
invalidate any implementations that don't use the flag (of which we have
several).

3. Only passing in a single boolean flag instead of an options class provider;
however, this is a more principled, futureproof API, which allows other
modules / awareness implementations to use their own options.

RELNOTES: --watchfs is now a command option; the startup option of the same
    name is deprecated. I.e., use bazel build --watchfs, not blaze --watchfs
    build.

--
MOS_MIGRATED_REVID=136026835

1 files changed, 2 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/DiffAwareness.java b/src/main/java/com/google/devtools/build/lib/skyframe/DiffAwareness.java
index f51cdfe281..64c90338d0 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/DiffAwareness.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/DiffAwareness.java
@@ -15,9 +15,8 @@ package com.google.devtools.build.lib.skyframe;
 
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
 import com.google.devtools.build.lib.vfs.Path;
-
+import com.google.devtools.common.options.OptionsClassProvider;
 import java.io.Closeable;
-
 import javax.annotation.Nullable;
 
 /**
@@ -55,7 +54,7 @@ public interface DiffAwareness extends Closeable {
    *     {@link DiffAwareness} instance. The {@link DiffAwareness} is expected to close itself in
    *     this case.
    */
-  View getCurrentView() throws BrokenDiffAwarenessException;
+  View getCurrentView(OptionsClassProvider options) throws BrokenDiffAwarenessException;
 
   /**
    * Returns the set of files of interest that have been modified between the given two views.