Fix an issue where setting the binary causes Firefox to be unable to start

Turns out we weren't populating things properly.

Author: shs96c

java/client/src/org/openqa/selenium/firefox/FirefoxDriver.java

@@ -166,23 +166,27 @@ public FirefoxDriver(Capabilities desiredCapabilities) {
 
   private static FirefoxOptions getFirefoxOptions(Capabilities capabilities) {
     FirefoxOptions options = new FirefoxOptions();
-    if (capabilities != null) {
-      Object rawOptions = capabilities.getCapability(FIREFOX_OPTIONS);
-      if (rawOptions != null) {
-        if (rawOptions instanceof Map) {
-          try {
-            @SuppressWarnings("unchecked")
-            Map<String, Object> map = (Map<String, Object>) rawOptions;
-            rawOptions = FirefoxOptions.fromJsonMap(map);
-          } catch (IOException e) {
-            throw new WebDriverException(e);
-          }
-        }
-        if (rawOptions != null && !(rawOptions instanceof FirefoxOptions)) {
-          throw new WebDriverException("Firefox option was set, but is not a FirefoxOption: " + rawOptions);
+
+    if (capabilities == null) {
+      return options;
+    }
+
+    Object rawOptions = capabilities.getCapability(FIREFOX_OPTIONS);
+    if (rawOptions != null) {
+      if (rawOptions instanceof Map) {
+        try {
+          @SuppressWarnings("unchecked")
+          Map<String, Object> map = (Map<String, Object>) rawOptions;
+          rawOptions = FirefoxOptions.fromJsonMap(map);
+        } catch (IOException e) {
+          throw new WebDriverException(e);
         }
-        options = (FirefoxOptions) rawOptions;
       }
+      if (rawOptions != null && !(rawOptions instanceof FirefoxOptions)) {
+        throw new WebDriverException(
+            "Firefox option was set, but is not a FirefoxOption: " + rawOptions);
+      }
+      options = (FirefoxOptions) rawOptions;
     }
     return options;
   }

java/client/src/org/openqa/selenium/firefox/FirefoxOptions.java

@@ -335,6 +335,18 @@ public FirefoxOptions addDesiredCapabilities(Capabilities desiredCapabilities) {
       }
       profile = suggestedProfile;
     }
+    Object binary = desiredCapabilities.getCapability(BINARY);
+    if (binary != null) {
+      if (binary instanceof File) {
+        setBinary(((File) binary).toPath());
+      } else if (binary instanceof FirefoxBinary) {
+        setBinary((FirefoxBinary) binary);
+      } else if (binary instanceof Path) {
+        setBinary((Path) binary);
+      } else if (binary instanceof String) {
+        setBinary((String) binary);
+      }
+    }
 
     return this;
   }