Small improvements for SuperDev.

1. Deactivate the PrecompressLinker if present.
2. Disable Symbol Maps.

Bug: issue 8881.
Change-Id: I99e035cc579925ea2ecb8ac02043dbc5daac6f8c
diff --git a/dev/codeserver/java/com/google/gwt/dev/codeserver/Recompiler.java b/dev/codeserver/java/com/google/gwt/dev/codeserver/Recompiler.java
index df034ff..247b4ee 100644
--- a/dev/codeserver/java/com/google/gwt/dev/codeserver/Recompiler.java
+++ b/dev/codeserver/java/com/google/gwt/dev/codeserver/Recompiler.java
@@ -405,6 +405,11 @@
       throw new UnableToCompleteException();
     }
 
+    // Deactivate precompress linker.
+    if (moduleDef.deactivateLinker("precompress")) {
+      logger.log(TreeLogger.WARN, "Deactivated PrecompressLinker");
+    }
+
     // Print a nice error if the superdevmode hook isn't present
     if (config.getStrings("devModeRedirectEnabled").isEmpty()) {
       throw new RuntimeException("devModeRedirectEnabled isn't set for module: " +
@@ -441,6 +446,7 @@
         "com/google/gwt/core/ext/linker/impl/properties.js");
 
     overrideBinding(moduleDef, "compiler.useSourceMaps", "true");
+    overrideBinding(moduleDef, "compiler.useSymbolMaps", "false");
     overrideBinding(moduleDef, "superdevmode", "on");
     return moduleDef;
   }
diff --git a/dev/core/src/com/google/gwt/dev/cfg/ModuleDef.java b/dev/core/src/com/google/gwt/dev/cfg/ModuleDef.java
index ca2d2e3..066524d 100644
--- a/dev/core/src/com/google/gwt/dev/cfg/ModuleDef.java
+++ b/dev/core/src/com/google/gwt/dev/cfg/ModuleDef.java
@@ -458,6 +458,13 @@
   }
 
   /**
+   * Deactivate a linker by name. Returns false if the linker was not active, true otherwise.
+   */
+  public boolean deactivateLinker(String linkerName) {
+    return activeLinkers.remove(linkerName);
+  }
+
+  /**
    * Associate a Linker class with a symbolic name. If the name had been
    * previously assigned, this method will redefine the name. If the redefined
    * linker had been previously added to the set of active linkers, the old